Letterman invited his 15-year, on-air competitor to come on his show his first free night.
"I think he'd be a great guest on [my] show," Letterman told Rolling Stone magazine. "The first night that he is out of a job, I think that would be a great situation."
The rivalry dates back to when Leno was given the nod over Letterman to be Johnny Carson's successor at NBC in 1993, leaving Letterman to set up shop at CBS.
Now that NBC has announced plans to keep Leno on the network in a new 10 p.m. show, it's unclear whether Letterman's offer still stands. If anything, it appears the rivalry continues. Leno joked during his monologue after the announcement of his new primetime show that Letterman would try to one-up him by changing his show to 9:59 p.m.
Letterman's only reference to Leno's new deal was at the beginning of his monologue that same night. "Welcome to the 'Late Show,'" he said. "Still at 11:35."