Is Jonah Hill a Little Monster? The actor admitted he totally crashed the set of Lady Gaga's new music video! Yes, this is the same shoot where Mother Monster was nipped by a wild creature!

Last night (Feb. 20) on 'Jimmy Kimmel Live,' Jonah explained how he stumbled onto the 'G.U.Y.' set.

"I said I wanted to take a little trip just to clear my head and get away from all of this Hollywood stuff and go somewhere pretty and different, where I wouldn't see anyone from work or anything," the Oscar-nominated actor said. "So I decided to go up to Hearst Castle, which was beautiful, up in Northern California."

As you might have guessed, the trip was not what Jonah expected!

"So I get there and I was supposed to have this private tour of the castle and I get there and they're shooting a Lady Gaga music video," he continued. "... There's trucks and lights and I'm like, 'Oh, no! This isn't a vacation at all!' And I knew all the teamster drivers. I'd worked with them on other films and stuff."

However, the actor is remaining tight-lipped about what he saw.

"I won't give away what the video's about because, you know, she's worked really hard on it, but I wasn't going to see 500 dancers in bookshelf hats ... and meat hats," he laughed. "It was great. It was a beautiful castle. It just wasn't the desired escape."