"X-Files" star David Duchovny will perform with Barenaked Ladies on NBC-TV's "The Tonight Show With Jay Leno" Friday night (Feb. 26). Duchovny, who's also slotted as a guest on the show, will provide backup vocals on "It's All Been Done Before." "They really like him, and they think the 'X-Files' is great," said Reprise Records president Howie Klein. The actor rehearsed with the rockers earlier Friday.