Having such a talented troupe allowed director Paul Feig to often just "let it ride."
"Since they all come from an improv background, they love just to take more cracks at it because it's just more opportunities to come up with funnier stuff," Feig said.
"They gave us a lot of freedom. And we loved it. Some of those takes went on til we rolled out of tape," said actress Wendi McClendon-Covey.
The stars all give credit for their quick thinking improv abilities to the Groundlings. And they all shared some of the important lessons they learned from their training.
"Don't play crazy for the sake of crazy," McCarthy said. "You can want something odd, but don't be crazy."
McClendon-Covey said the best advice is to listen.
"Let the other person have their moment, don't steam roll," said McClendon-Covey.
Maya Rudolph says having her improv background gives her a sense of confidence.
"Even when you're working on the show, I know a lot of times some actors would come to 'SNL' and say, 'I can't be funny like you guys.' It's like they think that we have some sort of secret language but it's a good skill set. And if it doesn't work for work, it's really good for parties," said the actress.
"Bridesmaids" is rated R for language and sexuality. It's in theaters on Friday, May 13.