HOLLYWOOD -- Rapper Snoop Dogg has a cameo in Old School.

During his number, a naked Will Ferrell grabs the mike and does his own excruciating solo.

"That was our last day of shooting. Standing that close to Snoop stark naked was really intimidating, but he was very good about it all," recalls Ferrell.

Because Vince Vaughn and Luke Wilson had little to do in the scene, the actors were in the trailers.

"Snoop's people came to my trailer where I was entertaining some friends and said Snoop wanted me to come over to his trailer because he was a fan," recalls Vaughn. "He wanted to play video games, so I brought my friends over and we all hung out and played video games."

Ferrell also dropped over.

It was not until everyone emptied out of the rapper's trailer at the end of the day that Wilson knew what was going on.

"I was in my trailer all alone watching TV. No one told me everyone was in Snoop's trailer.

"Vince was sort of speaking-in-tongues having spent that long with Snoop. I could barely understand what he was talking about," says Wilson.