In the film, Vaughn plays a guy thrilled at the prospect of fatherhood. Of course, there is another matter about to throw a wrench -- maybe the whole toolbox -- into his plans.
It turns out that in college, Vaughn's character was a frequent donor to a sperm bank. Due to a mix-up at the bank, his donations were used like an ATM machine, dispensing children by the hundreds.
"In kind of a messed up way, it's about family. And it's really about, you know, connecting with people in a way that it's nice to be loved but it's also nice to have people to love," said Vaughn.
He sneaks around learning about the young adults suing to learn their dad's identity, all the while, trying to help them.
"I feel like I'm returning to some of the stuff I had done younger where you get a chance to be more dramatic in the movie and have some more kind of sentimental or dramatic scenes," said Vaughn. "So that was just, for me, I felt very grateful to have that opportunity."
"Delivery Man" co-stars Cobie Smulders as his girlfriend and Chris Pratt as his lawyer and best friend.
Vaughn himself became a father at 40. Now 43, he has two small children, a toddler daughter and an infant son.
"I was fortunate that I was able to kind of have some time to mature and, you know, do some growing up," said Vaughn. "And then you get to a place in your life where you're ready to focus on that. So for me it was something I was excited about."
"Delivery Man" is based on the recent French-Canadian film "Starbuck." And the story closely mirrors that foreign-language film. In fact it's directed and co-written by the same guy who made "Starbuck," Ken Scott.
"Delivery Man" is rated "PG-13" and opens Friday.