While Maria Shriver is excited to welcome her first grandchild when daughter Katherine Schwarzenegger gives birth, she’s not quite as happy to take on the title of “grandma.”

“I’m not embracing that name exactly,” she joked to “Entertainment Tonight. “I’m gonna come up with my own name. I’ll just be Mama. No, I can’t do that. I’ve got to do something else. I’ll think of it. I’ll figure it out.”

Shriver, 64, added of Katherine, 30, and husband Chris Pratt, “I’m really proud of her. Obviously, she and Chris are super happy. They’re a blessing to each other.”

Shriver shares four children with ex-husband Arnold Schwarzenegger: Katherine, Patrick, Christina and Christopher.

Patrick, 26, told “ET” it’s “weird” to think about his new title too, saying: “I always forget you’re going to be a grandma. I guess I’m gonna be an uncle. That’s weird too.”

Katherine and Pratt, 40, tied the knot in June 2019 and news of her pregnancy broke last month.