'The Little Mermaid' Behind-The-Scenes Clip: Watch Melissa McCarthy Sing as Ursula (Exclusive)

Lin-Manuel Miranda gushes over the actress' 'sexy' and 'scary' performance.

Melissa McCarthy is living the fever dream! The 52-year-old actress is letting fans in on the musical process of becoming Ursula in Disney's live-action The Little Mermaid film in a new behind-the-scenes featurette. 

"Getting to sing 'Poor Unfortunate Souls,' I mean, it is a fever dream," McCarthy says in the clip. "I went to rehearsals for months and months, and I wanted to do that music and the character proud."

The A-list star suggests that her character may have missed her calling as a sultry chanteuse. 

"Ursula just would have been the greatest lounge act," McCarthy gushes. "Like, she should be just like slinked over a bar and, you know, singing into the wee hours." 

But as McCarthy got her own sea legs under her, she admits to working through some nerves when it came to performing in front of composer Alan Menken and producer/lyricist Lin-Manuel Miranda.

"It was great that it was so terrifying and so exciting at the same time," she recalls. "There was a moment when Alan and Lin popped in and it was like an early rehearsal, but they were like, 'Do you want us to sit in on your rehearsal?' I was like, 'I do not.'"

She quips, "It's like playing with Michael Jordan the first time you hold a basketball. I was like, 'Uh, no.'"

When it comes to Miranda, he has nothing but high praise for the Emmy Award winner. 

"She sings the hell out of it," he says. "She's sexy, she's scary, it's just all these different colors and flavors. Yeah, it's awesome."

Speaking with ET ahead of the film's May 26 release, McCarthy previously praised Halle Bailey's rendition of Princess Ariel's iconic tune, "Part of Your World," saying she is "so proud" of her co-star.

"I'm telling you, it's like I almost get choked up. When she finishes that song, I literally burst out crying, I was clapping, I was breathing weirdly and I literally wanted to stand up and be like, 'It's not just 'cause you are an amazing actress. It's not because your voice is from another planet, it [is you],'" she recalled. "It was how she chose to portray that strong, yet vulnerable woman. And I think it's a game changer and I think kids are going to look up to her and be like, 'That is me. I can do anything. I can choose the course of my destiny.' I think she just played it with such incredible strength and vulnerability at the same time, that was perfect."

Disney's The Little Mermaid is now available on Digital Retailers and will be available on 4K Ultra HD, Blu-ray and DVD on Sept. 19.