It's been four years since Jay Leno hung up his shoes as host of The Tonight Show, but he made a special appearance last night after Jimmy Fallon became 'injured' in the midst of his opening monologue.

Fallon needed someone to tag in for him, and luckily Leno was on hand to tell a few jokes to the audience.

Although Leno has been busy with Jay Leno's Garage and various stand-up endeavours over the last few years, we can't deny that we'd like to see him back in the host's chair of a talk show at some point... should Fallon be watching his back?

Watch it below: