Ryan Reynolds, Samuel L. Jackson on their new 'buddy action-mance'

— -- The dynamic duo of Ryan Reynolds and Samuel L. Jackson opened up in an interview with "Good Morning America" about working together for the first time in their upcoming film, "The Hitman's Bodyguard," which Reynolds describes as "a buddy action-mance," with "a bit of romantic comedy."

Jackson said he would describe the new film as "an action rom-com."

The film follows Reynolds' character, who is charged with the task of protecting a notorious hitman, played by Jackson, so that he can testify in court.

Reynolds told ABC News he had a "gut feeling" that he would work well with Jackson, whom he calls "the new Reverend Al Green," because of his singing abilities.

In addition to singing in the new film, Jackson also debuted his songwriting talents, revealing that he was asked to improvise the lyrics for a song during one scene.

"They actually came back and asked me to write the rest of that song," Jackson said. "And I'm just waiting on my ASCAP credit to kick in."

Jackson said he was excited about making the new movie because, "I mean, number one, Ryan. You know, being able to be in a film with him," adding that he is also a big fan of action films.

Reynolds revealed that working with Jackson is "something I've wanted to do forever."

"When he said yes, it was like, 'Oh, this is great! So I knew that I would have ... a partner in crime," Reynolds said.

Reynolds said he would describe his character in the upcoming film as "an emotional moron."

Jackson added that Reynolds' character isn't all bad, saying, "he's so good at his job, he's just bad at life."