Freddie Prinze Jr. says Kiefer Sutherland is ''the most unprofessional'' person he's ever worked with.

The 38-year-old actor, who has two children, Charlotte, four, and Rocky, 22-months, with wife Sarah Michelle Gellar, claims the '24' star, 47, made him want to quit acting completely after he co-starred on the TV series in 2010.

Speaking about his decision to take a hiatus from Hollywood, Freddie told ABC News while promoting his new Disney XD series 'Star Wars Rebels' at Comic-Con in San Diego, California: ''I did '24' ... it was terrible. I hated every moment of it. I just wanted to quit the business after that. So, I just sort of stopped.

''Kiefer was the most unprofessional dude in the world. That's not me talking trash, I'd say it to his face. I think everyone that's worked with him has said that.''

The 'She's All That' star also poked fun at Kiefer's height, adding: ''I went and worked for Vince Mcmahon at the WWE, for Christ's sake ... but, at least he was cool and tall. I didn't have to take my shoes off to do scenes with him, which they made me do [at '24']. Just put the guy on an apple box or don't hire me next time. You know I'm 6 feet and he's 5'4.''