Jimmy Fallon has settled on Will Smith and U2 as the guests for his Feb. 17 debut on ‘The Tonight Show.”

Fallon was low-key and looked a little tired Sunday as he discussed plans for the regime change at the latenight institution. He’s been in regular contact with his predecessor Jay Leno, who gave him an important piece of advice.

“He said ‘You have to make your monologue longer,’ ” Fallon said. On “Late Night” Fallon’s monologues have been running three to four minutes; Leno’s run about nine to 10. Leno impressed upon Fallon the importance to covering a good slice of the day’s big news.

Fallon said he intends to continue to do the taped skits and bits that have been a highlight of his five-year tenure on “Late Night.” Moving the show back to New York was a priority for him, but he said he intends to travel to Los Angeles at least twice a year.

Most of all, when pressed to define the difference of what he’ll do on “Tonight” versus “Late Night,” Fallon emphasized that he wanted to keep the “Tonight Show” a light, fun experience for viewers.

“It should be goofy and funny and make people laugh,” Fallon said. “That’s our job. …I wish Steve Allen and Johnny Carson were still around to see what we’re doing to do with the show.”

“Tonight” producer Josh Lieb noted that Fallon has never been accused to being too hip for the room, which should serve him well in making the move to 11:35 p.m.

“He’s the least exclusive comedian I know,” Lieb said. “He wants everyone to laugh with him.”