Amanda Seyfried rooting for Sabrina Carpenter to join potential 'Mamma Mia!' 3

She's working late, cause she's a singer (and an actress).

Amanda Seyfried is rooting for Sabrina Carpenter to join a potential third Mamma Mia! film.

"Mamma Mia 3, let's go baby," Seyfried told ABC News Live. "Everybody says it's gonna happen. But I mean, I haven't seen a script."

As part of Sabrina's Short n' Sweet tour, the pop star sings a different cover song at each concert. She performed the musical's title ABBA track during her recent Madison Square Garden show in New York City, which prompted Seyfried to agree that Sabrina could play her character Sophie's daughter in a third Mamma Mia! film.

Never mind the fact that Seyfried is just 13 years older than Sabrina — that's on par with the franchise, which saw Cher, who is three years older than Meryl Streep, play the latter's mother in the second film, the interviewer said.

“You’re right, actually, [it] doesn’t matter,” Seyfried said. “You know what? Old age makeup for me. That’s what it will be. … I’m an actor. I’ll do it. If Sabrina Carpenter wants to play my daughter, I’ll make it happen. It’s fine. I’m a big fan.”