Macaulay CulkinandBrenda Songare adding another chapter to their love story.

The couple, who are parents to a9-month-old son Dakota, got engaged after four years together, a source told PEOPLE on Wednesday.

Song, 33, was recently photographed sporting a diamond ring on her left hand while out and about in Beverly Hills, California, on Monday.

TheDollfaceactress and Culkin, 41, met on the set of their movieChangelandin Thailand and werefirst spotted togetherin July 2017.

While the two actors are notable stars, they’ve kept their relationship private on social media, except for special occasions, like when Song posted a photo of them on a date night in November at an L.A. Rams game.

For more on Macaulay Culkin and Brenda Song’s engagement, listen below toour daily podcast on PEOPLE Every Day.

“Very few things can get us out of the house and away from our son,” she wrote in the caption.

Song also wished Culkin a happy 40th birthday in a post on August 2020. The photo showed them wearing matching plaid pj’s with their respective names on them.

“Happy 40th birthday to this magical being,” she wrote in the caption. “I could sit here and write endlessly about how wonderful, kind, loving, genuine, loyal, honest, brilliant and hilarious you are, and how grateful I am that I get to share and do this life thing with you.”

Brenda Song and Macaulay Culkin.Backgrid

Brenda SOng

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The couple welcomed their son, Dakota, in April of last year naming him after Culkin’s late sister Dakota.

“We’re overjoyed,” Culkin and Song said in a brief statement about the arrival of their first child.

“This one’s a good one, so I’m probably going to put some babies in her in a little bit,” Culkin said, laughing. “I mean, we’ve definitely been practicing.”

He continued, saying he and Song have “a good life.”

“I have a pretty little family — a pretty girl, a pretty dog, a pretty cat, and all that stuff. We’re gonna move,” he said at the time. “We’re doing the house thing and all that kind of stuff.”

Macaulay Culkin (left); Brenda Song.Dimitrios Kambouris/WireImage; Barry King/Getty

macaulay-culkin-brenda-song.jpg

When theHome Alonestar appeared on thecover ofEsquirein February 2020, Song told the magazine what drew her to her fiancé.

“People don’t realize how incredibly kind and loyal and sweet and smart he is,” said Song. “Truly what makes Mack so special is that he is so unapologetically Mack.”

She continued: “He knows who he is, and he’s 100 percent okay with that. And that to me is an incredibly sexy quality.”

source: people.com