Jane and Jim Carrey

Jim Carrey is prepping for a huge new role — as a grandpa.

Check out pictures of Jim Carrey through the years

Carrey's 21-year-old daughter, Jane, is expecting her first child with rocker fiancé Alex Santana, who performs in the band Blood Money under the stage name Nitro.

"I'm very excited," Carrey told Us. "Jane is going to be a great mom."

McCarthy talks about Carrey's weight gain for Three Stooges

Carrey, 47, had Jane with ex-wife Melissa Womer, whom he divorced in 1997. He has dated Jenny McCarthy for more than four years. McCarthy has a son Evan, 7, who suffers from autism.