Katherine Schwarzeneggercan’t get enough of herfiancé Chris Pratt— or her engagement ring!

The 29-year-old showed off her diamond engagement ring in a sweet Instagram post she shared on Friday in support of Pratt’sThe Lego Movie 2: The Second Part— which debuted in theaters today.

She added, “Head to the theater tonight with your friends, family, kids or even with your pup! It’s so much fun and all about the power friendship! Yayyyyy LEGO ! 🥰♥️👏”

Christina Schwarzenegger comment on katherine schwarzenegger instagram post https://www.instagram.com/p/BtoUkcTBZyy/

katherine schwarzenegger

Her younger sister, Christina, 27, commented on the photo, writing, “You get that [ring emoji] shot hunnay.”

Schwarzenegger’s stunning ring includes an oval center stone, which appears to be set on a very thin simple band.

Jewelry expertJason Arasheben of Jason Beverly Hillstold PEOPLE Schwarzenegger’s ring appears to be a 5-carat diamond, which he says can range anywhere in price from $150,000 to $550,000.

Pratt, 39, announced their engagement on Instagram last month, writing, “Sweet Katherine, so happy you said yes! I’m thrilled to be marrying you. Proud to live boldly in faith with you. Here we go! 💍🙏♥️.”

RELATED VIDEO:Chris PrattandKatherine SchwarzeneggerAre Engaged: ‘Sweet Katherine, So Happy You Said Yes!’

His relationship with Schwarzenegger first heated up 10 months after the actor’s separation, when the couple wasspotted out together on Father’s Dayhaving a picnic in the park in Santa Barbara. They were later seen on dates around Los Angeles and outings with Pratt’s six-year-old son Jack in tow.

“They’re both serious about the relationship and hopeful for the future,” a source close to the couple told PEOPLE. “Chris doesn’t just date to date, and neither does Katherine. She’s very excited.”

“Chris and Katherine are very happy together,” added the source. “They’re very compatible and have a lot in common.”

The engagement comes a year and a half after Pratt announced his separation fromAnna Farisin August 2017 after almost nine years of marriage.

source: people.com