When Jimmy Fallon turns 40, it's a big deal. Sure, even the average joe thinks the big four-oh is worth commemorating, but Fallon has been working in the entertainment industry for years now, so obviously his peers were going to stand up and take notice of his milestone birthday.

So yesterday (September 19), his co-workers told him it'd be a special guest that Fallon would then interview.

"I am going to interview him or her," he said, before a call from offstage ominously added "Or it!" Fallon's quizzical response to this was priceless.

So when a three tier baby blue layer cake emerged from behind the curtain, the "it" comment seemed to be explained. But of course, a topless Seth Rogen jumped out... followed by James Franco, also topless, and swinging hand cuffs around his head.

I'll let you watch the rest of the joyful birthday celebration unfold—because there's another layer to it—but it was one fitting of the humor and laughter that Fallon has brought to countless people in his life.