The actress is already mother to sons Noah (12), Bodhi (10) and Journey (8) with her ex-husband Brian Austin Green

Megan Fox is making sure she’s in the right mindset as she embarks on her fourth pregnancy.

The Jennifer’s body alum, 38, spoke to PEOPLE about her collaboration with REVOLVE and shared that she has made some lifestyle changes since announcing that she is expecting her fourth baby, her first with fiancée Machine Gun Kelly.

“Being child #4, I’ve already learned all the tricks to making my body feel good physically and mentally,” Fox tells PEOPLE. “I sleep, exercise and stick to my healthy diet and lifestyle as always.”

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Related: Pregnant Megan Fox Shares Her Kids’ Reactions Upon Learning She’s Expecting Baby #4 (Exclusive)

Elsewhere in the interview, Fox opened up about how her children – sons Noah, 12, Bodhi, 10, and Journey, 8, who she shares with ex-husband Brian Austin Green – reacted when they found out she was a would have a younger sibling.

“The children are all very excited about the addition of another family member and have promised to come along and help out,” Fox said.

Last week, Kelly, born Colson Baker, spoke out for the first time since Fox announced she was pregnant with the couple’s first child together, giving an update on his new music and pointing out that he’s about to become a father again. Kelly is already father to 15-year-old daughter Casie, who he shares with his ex Emma Cannon.

In a post on “

“After all, I’ll soon be a father again!” Kelly ended his contribution in a friendly manner.

In early November, Fox announced the couple’s exciting baby news. The actress cradled her baby bump while it was covered in black fluid in an Instagram post, and in another snap, she held up a positive pregnancy test to the camera.

“Nothing is ever truly lost. Welcome back 👼🏼❤️,” she captioned the post, using lyrics from Kelly’s track “last November,” a song about his and Fox’s past pregnancy loss.