The 2013-2014 season may be the last for "Tonight Show" host Jay Leno, sources tell the Hollywood Reporter.

Late Night News: Jay Leno to Retire?
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"Late Night" host Jimmy Fallon is expected to replace Leno by summer 2014, moving to the coveted 11:35 PM time slot.

Sources say the network will bring in Fallon out of concern with ABC competition, Jimmy Kimmel, who moved to 11:35 PM in January. “The more time Jimmy Kimmel is in that slot, the more the young audience goes that way, the harder it is for Jimmy [Fallon] to keep that audience.”

NBC will reportedly make a public confirmation of the transition during May upfronts.

Leno's rep told THR, "We do not speculate on rumor."