Sarah Michelle Gellar

FREDDIE Prinze Jr is quickly gaining a reputation as Hollywood’s most sickening prankster.

The Scooby Doo star’s favourite tricks include dressing as a serial-killer and defecating in trailers on film sets.

Freddie, 30, who is married to Buffy star Sarah Michelle Gellar, told the New York Daily News: “The actress Claire Forlani had watched a documentary on serial killers so I dressed up as one of them.

“I was all in black with a T-shirt pulled over my eyes and I knocked on her door with a kitchen knife. I apologised to her afterwards.

“Another time Matt Lillard thought it was funny to defecate in my hotel room and it was. It made me laugh so I defecated in his trailer. It made him laugh.”