Chris Pratt and Katherine Schwarzenegger 'Always Hoped' for Younger Sibling for Daughter Lyla

Chris Pratt and Katherine Schwarzenegger are over the moon about baby No. 2!

The couple, who are parents to daughter Lyla, 16 months, are expecting their second child together, sources confirmed to PEOPLE on Thursday. Pratt, 42, is also dad to son Jack, 9, whom he shares with ex-wife Anna Faris.

Schwarzenegger, 32, and Pratt are "ecstatic" about the new addition to their family, a source tells PEOPLE. "They always hoped for Lyla to have another sibling. They feel very blessed," the insider says.

The insider adds that Schwarzenegger "loves being a mom. Lyla is her world. She has help, but is also very hands-on."

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The couple can also count on Schwarzenegger's mom, Maria Shriver, says the source: "Maria is also very involved in Lyla's life. She is excited for another grandchild."

Schwarzenegger and Pratt wed in June 2019 and welcomed Lyla in August 2020. The news of the newest addition to their family came shortly after Pratt wished Schwarzenegger a happy 32nd birthday on Instagram, praising her for being "​​a wonderful wife, mother, step-mother, and life partner."

Pratt wrote, "I simply can't imagine how lost I'd be without you. ... You're beautiful, tough as nails, reasonable, deeply thoughtful, extraordinarily smart, you're a complete boss, eternally driven and you communicate like no other."

In July, Pratt teased the possibility of having more children with Schwarzenegger, telling E! News' Daily Pop that he would "love" to become a dad again.

"I'll probably have to talk to Katherine about that," he said, "but my plan is, let's go."

Pratt also told Daily Pop about his "really beautiful" experience as a dad of two, explaining, "I think having a second child really emphasizes what was unique about your first child because when you have one kid, you just take for granted all their growth and development. You just assume all children are that way."