Imagine waking up one day and discovering that you have 533 children you didn't know about. This is the dilemma that David Wozniak (Vince Vaughn) faces after years of being a sperm donor. And now, some of his now-grown and younger children have petitioned the sperm bank to reveal his identity in Delivery Man.
The movie explores the themes of fatherhood, emotional maturity, and personal responsibility, while at the same time being funny and sweet. It's a difficult line to walk, especially for an actor best known for his performances in more straight-forward comedies.
PICS: Daddy Duty: Hollywood's Hottest Pops!
"This movie, in particular, I think is very different. This movie is very funny. It's a fun movie. But it's partially funny because it's very unpredictable.
It's got a lot of sentimental stuff in it, dramatic moments, some very tense moments in it as well," Vaughn told ET's special correspondent Jackie Johnson during the red carpet premiere of Delivery Man at the El Capitan Theater in Hollywood on November 3. "It was fun just being a part of this one."
In the film, Vaughn interacts with many of his 533 kids. For some working with younger actors can be challenging, but Vaughn says that, during this film, the experience was wonderful.
RELATED: Vince Vaughn: Delivery Man Guardian Angel?
"All the young actors are great," Vaughn said. "They do such a nice job and they were so enthusiastic, and all there story lines were so powerful. It was really easy just to show up every day and have fun."
Delivery Man was written and directed by Ken Scott, and is actually an American remake of Scott's 2011 French-Canadian film Starbuck.
Check out the video of the red-carpet premiere and hear from the other stars on what it was like working with Vaughn and developing a heartfelt comedy.
Delivery Man hits theaters November 22.