Fat and frightening Seth Rogen

Mar 25, 2009, 11:00 GMT

03/22/2009 - Seth Rogen - "Monsters vs. Aliens" Los Angeles Premiere - Arrivals - Gibson Amphitheatre - Universal City, CA, USA © David Gabber / PR Photos

Seth Rogen claims he terrifies young children.

The comic star - who provides the voice of B.O.B. in new movie 'Monsters vs. Aliens' - believes kids find him intimidating because he is fat and hairy.

He said: "I did a meet-and-greet with kids after the premiere in Australia. I realised kids just don't like Seth Rogen. I scare the sh*t out of them. Maybe it's my laugh or that I'm a big, hairy guy. They just don't like me."

Seth was delighted to lend his voice to the character of B.O.B. - short for Bicarbonate Ostylezene Benzoate - because he thinks he is the funniest character in the film.

The actor - who was the voice behind Morton the Mouse in 'Horton Hears a Who!' and Mantis in 'Kung Fu Panda' - said: "Mantis was one of the Furious Five, who were the straight men to Jack Black. In 'Horton', Jim Carrey was the funny one. Now, B.O.B. is the funny one. He doesn't know what is going on and doesn't care. He's just thrilled to be involved in something and is unflappably happy."

Seth also revealed it was great to record his lines alone because it meant he couldn't annoy his co-stars.

He told USA Today newspaper: "You can focus on your own thing and have total control. I could play with one line for an hour without Reese Witherspoon tapping her foot on the floor."