The Unauthorized Full House Story stars Garrett Brawith and Justin Gaston remember the heyday of Full House just like everyone else, so even they were surprised by some of the dirty secrets they found out about the TV family.

Full House provided wholesome entertainment for the entire family on ABC back in the '80s and '90s, but life on set may not have been all fun and games, at least according to Lifetime's upcoming TV movie.

WATCH: Get Your First Look at Lifetime's Unauthorized 'Full House' TV Movie

"When I heard that John [Stamos] came out and said that he did try to get the twins fired, I actually was pretty shocked," Gaston told ET.

Gaston (who plays John Stamos/Uncle Jesse) and Brawith (playing Bob Saget/Danny Tanner) feel confident in their performances, but the one thing they're unsure of is how the real-life stars they're portraying will react to the biopic.

"Sooner or later, Bob is going to see this, and we are either going to go out for drinks or he is going to beat me up," Brawith kidded.

WATCH: Full House Cast Reunites, Performs the Theme Song!

ET was on the Full House set in the '80s and '90s, and from years of coverage, it's our belief Lifetime captured the silly banter that went on between the cast members behind the scenes. For instance, in 1987, Saget broke up an interview with co-stars Dave Coulier and Stamos!

The Unauthorized Full House Story, also starring Justin Mader as Coulier and Stephanie Bennett as Lori Loughlin, airs Saturday at 8 p.m. ET/PT on Lifetime.

Click the video below to learn about the official Full House revival, Fuller House, that's heading to Netflix.