Duff announced the news Thursday on Instagram, showing off her ring in two sweet selfies of the couple.

“He asked me to be his wife,” she captioned the post.

Koma posted the same photos, writing: “I asked my best friend to marry me… @hilaryduff.”

View this post on Instagram

He asked me to be his wife??

A post shared by Hilary Duff (@hilaryduff) on May 9, 2019 at 7:20am PDT

The Younger actress was first linked to Koma, a singer/songwriter, in early 2017. They broke things off a few months later in March, but by September, Duff had started dropping hints that she and Koma, 31, were back together, sharing Polaroids of herself strumming a guitar and blowing out the candles on her birthday cake.

The couple soon reunited for good, and they’ve been going strong ever since.

In June 2018, Duff, 31, announced she and Koma were expecting.

“Guess what guys! @matthewkoma and I made a little princess of our own and we couldn’t be more excited!!!!!” she captioned a photo of him sweetly kissing her cheek as she showed off her growing baby bump.

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Guess what guys! @matthewkoma and I made a little princess of our own and we couldn’t be more excited!!!!!!????????????????????

A post shared by Hilary Duff (@hilaryduff) on Jun 8, 2018 at 9:43am PDT

RELATED VIDEO: Hilary Duff Is Pregnant! Actress Expecting ‘a Little Princess’ with Boyfriend Matthew Koma

The couple welcomed daughter Banks Violet Bair on Oct. 25.

“This little bit has fully stolen our hearts!” Duff gushed on Instagram. “She joined our world at home on Thursday afternoon and is absolute magic.”

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Banks Violet Bair?? this little bit has fully stolen our hearts! She joined our world at home on Thursday afternoon and is absolute magic ?

A post shared by Hilary Duff (@hilaryduff) on Oct 29, 2018 at 6:38pm PDT

RELATED: Hilary Duff Opens Up About Her Home Water Birth with Daughter Banks: ‘It Was, Like, Five Pushes’

Banks’ name has multiple family ties, even if they weren’t intentional. Duff previously revealed the couple agreed on the moniker “right away” and loved it in general after initially thinking they would name their daughter Violet, which turned into her middle name.

But two days before Duff gave birth, Koma Googled the name “Banks Bair” (Bair is his given last name) and unearthed a big surprise.

“He found relatives — Bair [ancestors] or whatever — that were William Banks Bair. Two of them. Isn’t that insane?” she said. “So it’s actually a family name.”

Duff also shares son Luca Cruz, 6, with ex-husband Mike Comrie.