Megan Fox and Machine Gun Kelly are expecting their first child together

Fox has three sons with ex Brian Austin Green, while Kelly has a teenage daughter.

Megan Fox is expanding her family.

The New Girl actress and fiancé Machine Gun Kelly, whose real name is Colson Baker, are expecting their first child together, Fox announced Monday on social media.

One snapshot showed Fox cradling her belly, while another featured her holding a positive pregnancy test. In the caption, she wrote, "nothing is ever really lost. welcome back."

Fox and Kelly confirmed their relationship in May 2020, months after meeting while making the 2021 film Midnight in the Switchgrass. They were engaged two years later.

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In Nov. 2023, she wrote in her book of poems, Pretty Boys Are Poisonous, about having experienced a miscarriage with her musical love interest.

"I've never been through anything like that in my life," Fox said while promoting the collection on Good Morning America. "I have three kids, so it was very difficult for both of us and it sent us on a very wild journey together and separately…trying to navigate, 'What does this mean?' and 'Why did this happen?'"

Both Fox and Kelly have children from previous relationships. Fox and ex-husband Brian Austin Green share three sons: Noah, 12; Bodhi, 10; and 8-year-old Journey. Kelly and ex Emma Cannon have a daughter, Casie, who's 15.

When her book was released, Fox said that her reason for writing it was to let women known they don't have to keep their pain to themselves.

Related: Megan Fox slams claim her kids are 'forced' to wear 'girls' clothes'

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"It gives an elegant place for your pain to live — to put it into art makes it useful to other people," Fox said. "And so, you don't just suffer with it on your own."

Fox has said that becoming a mother came at exactly the right time for her. "That kind of saved me, honestly," she told The Washington Post in July 2021. It prompted her to look outside the entertainment industry and find "purpose."