Josh Duhamel Announces Engagement to Audra Mari — and Gets Congratulations from Ex Fergie

Josh Duhamel and Audra Mari are engaged!

The Transformers star, 49, who has been dating Mari since 2019 following his divorce from Fergie, announced the happy news Saturday on Instagram with a photo of the couple posing by the beach.

"It's on!! She found a message in a bottle that washed ashore and said YES!! @audramari," the actor captioned the shot of the pair smiling, while he held up a handwritten letter that read: "Audra Diane Mari Will You Marry Me?"

The Jan. 8 proposal also marked another special occasion — Mari's 28th birthday.

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Fergie, 46, celebrated the couple in the comment section, writing, "Congrats!!!💚💚💚💚💚💚."

In December 2019, a source told PEOPLE that Duhamel was "really happy" with the former Miss World America, whom he'd begun "dating seven or eight months" prior.

The source's comment came amid a holiday party the two attended together that month, at which Duhamel and Mari "were basically together all night," an onlooker told PEOPLE at the time.

While it was not the pair's first time spotted out together, the party took place about two weeks after Duhamel's divorce from ex-wife Fergie was finalized.

RELATED VIDEO: Josh Duhamel Steps Out with Audra Mari Weeks After His Divorce from Fergie Was Finalized

After eight years of marriage, Fergie filed for divorce in late May 2019, nearly two years after she and Duhamel announced their split in a joint statement obtained by PEOPLE in September 2017.

"With absolute love and respect we decided to separate as a couple earlier this year," they said. "To give our family the best opportunity to adjust, we wanted to keep this a private matter before sharing it with the public."

Added the former couple, who share 8-year-old son Axl Jack, "We are and will always be united in our support of each other and our family."

During a 2018 episode of Dax Shepard's Armchair Expert podcast, Duhamel opened up about what he's looking forward to in the next stage of his life — including settling down again following his separation from the former Black Eyed Peas singer.

"I'm not 30 years old anymore. I'm 45. I want to have more kids in the next few years," Duhamel said at the time. "So it's more about finding someone young enough to have kids. It's not as if I'm out there trying to just f--- anything. That's not who I am. I'm trying to find a girl that I can be with and have a family with."