"Tonight, tonight, who's going to host 'Tonight?' Is it going to be Jimmy or Jay?" the pair sang in a parody of "Tonight" from the Broadway musical "West Side Story."

The rumor mill has Fallon, 38, taking over 62-year-old Leno's job as host of NBC's "Tonight Show," and Leno has responded with pointed barbs at his employer that have seen his ratings rise.

"In the news, they say I'm replacing you, they think that I can woo, the demo," Fallon sang.

Kimmel: Leno dumbs down his material

Late night war rages with Fallon, Leno

Bill Carter: Fallon is replacing Leno

Jimmy Fallon's takeover of "The Tonight Show" has been inevitable, show producer Lorne Michaels told GQ. "He's the closest to (Johnny) Carson that I've seen of this generation," Michaels said. Fallon, who rose to fame as a cast member on "Saturday Night Live" from 1998-2004, currently hosts the late-night talk show "Late Night with Jimmy Fallon." Pictured, Fallon chats with Olympic swimmer Ryan Lochte on the show. Here's a look at the other "Tonight Show" hosts.

Comedian and songwriter Steve Allen was the show's first host, from 1954 to 1957. His prolific career earned him two stars on the Hollywood Walk of Fame. Pictured, Allen poses for a promotional portrait, 1955.

Jack Paar's unpredictable and dramatic presence drew more than 7 million viewers every night between 1957 and 1962. The show was renamed "The Jack Paar Show" while he was host. Paar is seen here on the set, sometime during his stint on the show.

Johnny Carson's 30 years as a host on the show made him a talk show icon. Carson, who hosted from 1962 to 1992, set the standard for late night show formats and style. Pictured, Carson speaks to a guest, 1964.

Jay Leno starred in "The Tonight Show with Jay Leno" from 1992 to 2009, then moved to his own primetime show, "The Jay Leno Show," on NBC. After a public controversy over scheduling changes while Conan O'Brien hosted the show in 2009, Leno returned to host "The Tonight Show" in 2010. Pictured, Leno jokes with actor/comedian Jerry Seinfeld, 1998.

Conan O'Brien hosted the show for seven months and left after NBC announced it would be moving his show to after midnight and Leno's primetime show to "The Tonight Show's" time slot. Pictured, O'Brien on his final show on January 22, 2010.

Leno returned in March 2010 and is currently the host. Pictured, Leno chats with President Barack Obama during a taping, October 2012.

Photos: 'Tonight Show' hosts

Jay Leno jokes about NBC

Leno responsed: "So the network says, here's an idea: pack your bags, take a hike, NBC-ya!"

We're still friends, right?

The carefully choreographed bit capped a day-long NBC promotional blitz that included a 30-second teaser video on Fallon's YouTube channel.

A beleaguered Leno exits the "Tonight Show" set in Los Angeles at the beginning of the four-minute skit, hounded by reporters asking him if the rumors of his demise are true.

Meanwhile in New York, a pensive-looking Fallon,surrounded by speculative press clippings in his dressing room, gets a call from Leno. "Hey kid, how you holding up?"

"Okay, I guess," Fallon answers. "You?"

"I'll live. I've been through this before you know," Leno deadpans. "I've got to admit I'm getting sick of all this."

Looking for reassurance, Fallon says: "Jay, can I ask you something? We're still friends, right?"

Leno: "Of course we're still friends."

Cue the orchestra

Confidence restored, Fallon breaks into song -- quickly followed by Leno -- with all the subtlety of, well, a show tune.

Although the bit had the apparent blessing of the network, there were no sacred cows.

Leno brags of his ratings, now at a seven-week high, even as NBC may be plotting to usher him off the air in favor of Fallon's appeal to younger demographic groups.

Talk about another network that might want to pick up a successful talk show host? Sure.

"I've got Fox on the line," Leno croons.

Maybe the comedians hate each other. Maybe they don't.

The entertainment press sure likes to pit the funnymen against each other.

But doesn't music make things better?

"Tonight, tonight, why do they say we fight?" the pair sang.

"I like you. You you like me. We're okay."

Convinced?

A bit of controversy

Rumors about Fallon supplanting Leno have been swirling since mid-March, when The New York Times' Bill Carter reported that the network has made a commitment to Fallon in regards to him succeeding Leno.

Yet according to Carter, Fallon's future as the new host of "Tonight" isn't a done deal as much as it's an understanding.

"There's no deal yet for the timetable of this, they have an understanding," Carter told CNN's Jake Tapper last month "I'm sure Jay knows about the understanding. But Jay has a contract that goes until the fall of next year. I think from Jay's point of view, he will work until they tell him to stop. That's the way he is; that's the kind of guy he is."

Still, the idea of Fallon getting the show isn't a surprise, at least, not as much as the report that the show will move back to New York from California.

"There's a lot of reasons for it. I think they all feel that the energy of New York helps Fallon," Carter said. "But also you have Lorne Michaels, who's the producer of the show, and has always been close to Jimmy, and he's of course New York-based.

"And then you have the band, The Roots, and The Roots are a Philadelphia-based band, and some of the guys I think still commute to New York, and they're very important to that show and I don't think they wanted to lose them."

The punchline

If the musical skit proves anything, Leno and Fallon haven't lost their sense of humor under the scrutiny of the future of the "Tonight Show."

They even couched it with a dose of reality.

In a pseudo-operatic climax, the pair asks:

"Tonight, tonight, who cares who hosts 'Tonight?'

"People just watch online the next day."

"Tonight, tonight, who's going to host 'Tonight?' Is it going to be Jimmy or Jay?" the pair sang in a parody of "Tonight" from the Broadway musical "West Side Story."

The rumor mill has Fallon, 38, taking over 62-year-old Leno's job as host of NBC's "Tonight Show," and Leno has responded with pointed barbs at his employer that have seen his ratings rise.

"In the news, they say I'm replacing you, they think that I can woo, the demo," Fallon sang.

Kimmel: Leno dumbs down his material

Late night war rages with Fallon, Leno

Bill Carter: Fallon is replacing Leno

Jimmy Fallon's takeover of "The Tonight Show" has been inevitable, show producer Lorne Michaels told GQ. "He's the closest to (Johnny) Carson that I've seen of this generation," Michaels said. Fallon, who rose to fame as a cast member on "Saturday Night Live" from 1998-2004, currently hosts the late-night talk show "Late Night with Jimmy Fallon." Pictured, Fallon chats with Olympic swimmer Ryan Lochte on the show. Here's a look at the other "Tonight Show" hosts.

Comedian and songwriter Steve Allen was the show's first host, from 1954 to 1957. His prolific career earned him two stars on the Hollywood Walk of Fame. Pictured, Allen poses for a promotional portrait, 1955.

Jack Paar's unpredictable and dramatic presence drew more than 7 million viewers every night between 1957 and 1962. The show was renamed "The Jack Paar Show" while he was host. Paar is seen here on the set, sometime during his stint on the show.

Johnny Carson's 30 years as a host on the show made him a talk show icon. Carson, who hosted from 1962 to 1992, set the standard for late night show formats and style. Pictured, Carson speaks to a guest, 1964.

Jay Leno starred in "The Tonight Show with Jay Leno" from 1992 to 2009, then moved to his own primetime show, "The Jay Leno Show," on NBC. After a public controversy over scheduling changes while Conan O'Brien hosted the show in 2009, Leno returned to host "The Tonight Show" in 2010. Pictured, Leno jokes with actor/comedian Jerry Seinfeld, 1998.

Conan O'Brien hosted the show for seven months and left after NBC announced it would be moving his show to after midnight and Leno's primetime show to "The Tonight Show's" time slot. Pictured, O'Brien on his final show on January 22, 2010.

Leno returned in March 2010 and is currently the host. Pictured, Leno chats with President Barack Obama during a taping, October 2012.

Photos: 'Tonight Show' hosts

Jay Leno jokes about NBC

Leno responsed: "So the network says, here's an idea: pack your bags, take a hike, NBC-ya!"

We're still friends, right?

The carefully choreographed bit capped a day-long NBC promotional blitz that included a 30-second teaser video on Fallon's YouTube channel.

A beleaguered Leno exits the "Tonight Show" set in Los Angeles at the beginning of the four-minute skit, hounded by reporters asking him if the rumors of his demise are true.

Meanwhile in New York, a pensive-looking Fallon,surrounded by speculative press clippings in his dressing room, gets a call from Leno. "Hey kid, how you holding up?"

"Okay, I guess," Fallon answers. "You?"

"I'll live. I've been through this before you know," Leno deadpans. "I've got to admit I'm getting sick of all this."

Looking for reassurance, Fallon says: "Jay, can I ask you something? We're still friends, right?"

Leno: "Of course we're still friends."

Cue the orchestra

Confidence restored, Fallon breaks into song -- quickly followed by Leno -- with all the subtlety of, well, a show tune.

Although the bit had the apparent blessing of the network, there were no sacred cows.

Leno brags of his ratings, now at a seven-week high, even as NBC may be plotting to usher him off the air in favor of Fallon's appeal to younger demographic groups.

Talk about another network that might want to pick up a successful talk show host? Sure.

"I've got Fox on the line," Leno croons.

Maybe the comedians hate each other. Maybe they don't.

The entertainment press sure likes to pit the funnymen against each other.

But doesn't music make things better?

"Tonight, tonight, why do they say we fight?" the pair sang.

"I like you. You you like me. We're okay."

Convinced?

A bit of controversy

Rumors about Fallon supplanting Leno have been swirling since mid-March, when The New York Times' Bill Carter reported that the network has made a commitment to Fallon in regards to him succeeding Leno.

Yet according to Carter, Fallon's future as the new host of "Tonight" isn't a done deal as much as it's an understanding.

"There's no deal yet for the timetable of this, they have an understanding," Carter told CNN's Jake Tapper last month "I'm sure Jay knows about the understanding. But Jay has a contract that goes until the fall of next year. I think from Jay's point of view, he will work until they tell him to stop. That's the way he is; that's the kind of guy he is."

Still, the idea of Fallon getting the show isn't a surprise, at least, not as much as the report that the show will move back to New York from California.

"There's a lot of reasons for it. I think they all feel that the energy of New York helps Fallon," Carter said. "But also you have Lorne Michaels, who's the producer of the show, and has always been close to Jimmy, and he's of course New York-based.

"And then you have the band, The Roots, and The Roots are a Philadelphia-based band, and some of the guys I think still commute to New York, and they're very important to that show and I don't think they wanted to lose them."

The punchline

If the musical skit proves anything, Leno and Fallon haven't lost their sense of humor under the scrutiny of the future of the "Tonight Show."

They even couched it with a dose of reality.

In a pseudo-operatic climax, the pair asks:

"Tonight, tonight, who cares who hosts 'Tonight?'

"People just watch online the next day."