Chris Pratt Makes His Romance with Katherine Schwarzenegger Instagram Official on Her Birthday

Chris Pratt is publicly raving about girlfriend Katherine Schwarzenegger for the first time!

In honor of her 29th birthday on Thursday, the actor, 39, shared some of his favorite photos of Schwarzenegger on Instagram and Twitter.

“Happy Birthday Chief! Your smile lights up the room. I’ve cherished our time together,” the father of one captioned his collage.

“Thrilled God put you in my life. Thankful for the laughs, kisses, talks, hikes, love and care,” Pratt concluded his sweet message.

Video: Chris Pratt 'Inseparable' From Katherine Schwarzenegger

Along with a selfie of the couple indulging in animal-print face masks, Pratt included photos of himself kissing her cheek as well as a smiley image of Schwarzenegger clipping her boyfriend’s toenails.

Not only does the cute post mark their romance as social media official, but it was also the first time fans got to see six never-before-seen candid moments of the couple.

RELATED: Chris Pratt & Katherine Schwarzenegger Enjoy Date with Her Dad: ‘Arnold Seemed Very Pleased with Him’

Pratt and Schwarzenegger were introduced by Schwarzenegger’s mother, Maria Shriver (her dad is actor Arnold) in June and it wasn’t long before the pair was spotted on a date together that same month.

Since the summer, they have been spotted riding bikes, going on multiple church dates together and hanging out with each other’s families — including Pratt’s son Jack, 6, with ex Anna Faris.

Though Pratt’s rep denied claims of an engagement in September, “Chris and Katherine are very happy together,” says a source close to the pair. “They’re very compatible and have a lot in common.”

“It’s only been a couple of months, but they’re both serious about the relationship and hopeful for the future,” the source said. “Chris doesn’t just date to date, and neither does Katherine. She’s very excited. Family is very important to both of them, as well as their spirituality. She’s very, very sweet and maternal and great with his son.”

RELATED: Chris Pratt & Katherine Schwarzenegger Were ‘Affectionate’ at Thanksgiving with Her Family: Source

Meanwhile, Pratt and Faris, 41, who has been dating cinematographer Michael Barrett, continue to amicably co-parent their son.

“They were all together for school activities,” an insider recently told PEOPLE. “They are very friendly and seem happy when they are together with their son.”

The exes filed for divorce and requested joint custody of Jack in December 2017 and recently photographed together with their 6-year-old as well as their significant others when they all celebrated Halloween together.

In addition, Pratt has developed a friendship with his girlfriend’s family.

On Tuesday night, the Jurassic World star was spotted having a blast with Schwarzenegger’s younger brother Patrick, 25, at the Staples Center where the Los Angeles Clippers played against the New York Knicks.