You'd be forgiven for thinking you'd somehow traveled back in time last night. Yes, that was former host Jay Leno delivering The Tonight Show monologue. No, he's not pulling a Conan on Jimmy Fallon.

Leno crashed the show as part of a promotion for his new CNBC program, Jay Leno's Garage. Fallon started his monologue as usual, then feigned an injury that would, of course, require a certain large-jawed, silver-haired replacement.

“I think I pulled a hammy on that last joke,” Fallon told the audience. “I don’t think I can continue. But of course, here at The Tonight Show, the monologue has to go on. So, I think I’m gonna have to sub out. Can someone can tag in for me, please?”

Leno, who left the show early last year, then appeared on stage to pinch hit. You can watch his monologue below. The Marco Rubio/"smartest Kardashian" joke is probably worth it alone.