Arnold Schwarzenegger Raves About Being a Grandfather, Talks 'Fantastic' Son-in-Law Chris Pratt

"When they come over the whole house lights up," the Terminator star said of his daughter Katherine, son-in-law Chris Pratt and granddaughter Lyla

Arnold Schwarzenegger is one proud patriarch!

While appearing on Jimmy Kimmel Live! Thursday, the 74-year-old actor gushed about his growing family. In December, PEOPLE confirmed that his daughter Katherine Schwarzenegger Pratt and her husband Chris Pratt are expecting their second baby together. The couple are parents to daughter Lyla, 1 ½.

Thanking host Jimmy Kimmel for sharing his congratulations on the news, Schwarzenegger said, "It's the easiest thing to be a grandfather."

"They come over to the house, you play with Lyla for around an hour or two, put her on the horse, put her with the dog. And after two hours, they leave," he joked, clapping his hands. "It's fantastic! I have a great time when they come over to the house."

Jimmy Kimmel Live/Youtube

Speaking about his son-in-law, the former governor of California called Pratt, 42, a "fantastic guy" and "a great son-in-law." Sharing similar praise for his author daughter, 32, he continued, "I love my daughter Katherine, is so wonderful and I'm so proud of her."

"When they come over the whole house lights up. And the animals are there," he said.

In the same conversation, Kimmel, 54, asked his guest if he knew the gender of his second grandchild.

"I don't know if they know – maybe it's going to be a surprise – what the baby's gender is. Would they tell you, or would they be worried that you would accidentally blow it?" the comedian asked.

"I really don't know. But I do blow it a lot of time, because I can't shut my mouth," Schwarzenegger joked. "It could easily be that they know, I don't know, I don't think so, because my wife never wanted to know. It was always a guessing kind of a game," he explained.

"I think because Katherine is a lot like Maria, she will probably go in the same direction and not want to know," the Terminator star speculated.

katherine schwarzenegger/instagram

In December, Schwarzenegger and his ex-wife Maria Shriver finalized their divorce 10 years after they split.

Shriver, 66, first filed for divorce in July 2011 after 25 years of marriage. Two months before the filing, Schwarzenegger publicly admitted he had fathered his son Joseph Baena with the family's longtime housekeeper Mildred Baena.

Schwarzenegger and Shriver share four kids together: daughters Katherine and Christina, 30, and sons Patrick, 28, and Christopher, 24. Schwarzenegger's son Joseph, is also 24.

When Shriver and Schwarzenegger announced their split in May 2011, they noted that their four kids are "the light and the center of both of our lives."

"This has been a time of great personal and professional transition for each of us," they said in a statement at the time. "After a great deal of thought, reflection, discussion and prayer, we came to this decision together."

The former couple has remained unified as a family since their breakup. In 2020, they celebrated Schwarzenegger's birthday together, with Shriver smiling in a photo on Instagram with her ex and their kids.