Bradley Cooper says he's retired his 'A Star is Born' voice

Feb. 15 (UPI) -- Bradley Cooper says he's retired the voice he used in A Star is Born.

The 44-year-old actor discussed on Thursday's episode of The Late Show with Stephen Colbert how he intentionally lowered his voice to play Jackson Maine in the film.

Cooper said he modeled his voice after co-star Sam Elliott, who portrays Jackson's brother, Bobby Maine, in the movie. The film also stars Lady Gaga as aspiring singer Ally Maine.

"I had to create a character," Cooper said. "Part of when I was knowing I wanted to do this movie and knowing [Lady Gaga] and wanting to sing everything live is that I had to create these guys -- they're so idiosyncratic and iconic and you know, they're rock stars."

"I knew I wanted to lower my voice but I didn't want to make him too country," he added. "Sam Elliott's from Sacramento; his mother is from Texas. So he has this accent you can't quite place, but it's so wonderfully iconic."

Cooper said he practiced regularly to perfect the voice for the film.

"First, I would do this warmup all the time and there was a tagline. The first six months I could only do it like this," the star said while bending over. "I would go to sleep and my throat would hurt. I thought, oh, this is never going to happen."

"That is what I was most terrified of -- this voice," he shared.

Cooper will perform with Lady Gaga at the Oscars ceremony Sunday. A Star is Born is nominated for eight Academy Awards, including Best Picture, Best Actor for Cooper and Best Actress for Lady Gaga.