Will Arnett takes center stage in Bradley Cooper's new film, "Is This Thing On?"

In one of his most dynamic roles yet, Arnett steps into the world of stand-up comedy in the Cooper-directed film about taking risks and realizing that it's never too late to follow your passions.

"I think that it's important to remember that we can have a shift of perspective," Arnett told "Good Morning America." "It's never too late to shift your perspective."

Arnett, who co-wrote the script with Cooper, plays Alex Novak, a father of two who is facing an impending divorce from his wife Tess (Laura Dern). As their marriage unravels, he seeks a new purpose in New York City's comedy scene.

A British comedian named John Bishop was the inspiration behind the story, according to Arnett. Like Alex, Arnett said that when he met Bishop, Bishop was also going through a divorce and had signed up for an open mic night at a pub because he didn't want to pay the cover charge.

"He went up, and then he started going week after week. He liked it, he was kinda getting relief from doing it," Arnett told ABC News' George Stephanopoulos in an interview that aired Friday on "GMA." "So, I loved that idea, and we started writing it."

Prior to the film, Arnett said he had never done stand-up comedy before.

"It's such a unique discipline, stand-up," he said. "I've always had a healthy fear of it, you know? So I'd never done it before until we started doing prep for the movie."

Cooper, who not only directed the film but also starred in the movie as Alex's best friend, told "GMA" that the role of Alex was one that he thought encapsulated Arnett's life.

"When I read it, the idea of him doing stand-up and knowing where he is in life now -- 55 and everything that he's been through -- I thought, 'Oh man,'" Cooper said. "I was like, 'This is a character that could really harness all of your talent.'"

He added, "I got excited about just shooting him doing stand-up. And I [have] loved stand-up comedy since I went to grad school [in New York City] in the late '90s."

Arnett and Cooper filmed scenes for the movie in the iconic Comedy Cellar in New York City, as well as other venues. Arnett said that when he and Cooper would go to the Comedy Cellar in the preparation stages of the film, Arnett would be introduced onstage as Alex.

Cooper said that what he wanted to achieve with the film was to show Alex's growth as he discovers himself through stand-up comedy.

"It's all about process, about somebody putting themselves in a situation that makes them feel uncomfortable, that they're forced to grow," he said. "And that's what the comedy, stand-up comedy element, serves for the story, 'cause the story really is about this marriage."

He added, "In showing himself in a way of growing, then he's able to ... communicate in his intimate relationship. But without that self-growth, it's very hard to communicate with your partner."

Alex's wife Tess, played by Dern, also goes through a transformation in the film, as she reconnects with what she was once passionate about.

Dern told "GMA" that she learned a lot about herself in the role of Tess and said the film's message of rediscovering one's purpose in life resonated with her.

"I've seen it in parenting, in love stories, in friendships, that we have to continue to redefine ourselves and be open to meeting ourselves over and over again in our life," she said. "That was a huge influence on me."

She added, "That was an incredible gift. And I learned an amazing deal about myself."

Also starring in the film are Andra Day, Christine Ebersole, Ciarán Hinds, Amy Sedaris, Sean Hayes and Scott Icenogle.

Will Arnett takes on stand-up comedy in new film with Bradley Cooper, Laura Dern