Inside Megan Fox and Brian Austin Green's 'Healthy' and 'Cordial' Co-Parenting Relationship

There's nothing but respect between Megan Fox and her ex-husband, Brian Austin Green, even as both stars have moved on with new, committed relationships.

A source tells ET that Fox and her fiancé, Machine Gun Kelly, have "blended together" with Green and his love, Sharna Burgess.

"Megan, MGK, Brian, and Sharna are all cordial," the source shares, adding that "Megan and Brian have a healthy co-parenting relationship."

Fox and Green share three sons -- Noah, 10, Bodhi, 8, and Journey, 6. He is also the dad of 20-year-old son Kassius, from his relationship with Vanessa Marcil, and recently welcomed his fifth son, Zane, with Burgess this past June.

"Sharna is doing fabulous as a new mom," the source says. "It's always been a dream of hers, and she and Brian are the real deal."

The source adds that Green "takes a lot of pride in this new chapter of his life."

Meanwhile, Fox and Kelly have been going strong since announcing their engagement in January, and the source says the pair are "still in the process of wedding planning, but things are very much underway."

"They are doing so amazing as a couple and they pretty much worship the ground that each other walks on," the source says. "MGK is so involved with her kids and they absolutely adore him."

Kelly, 32, also is the father to 13-year-old daughter Cassie. Another source told ET over the summer that the couple is open to having children together.

"Megan and Machine Gun Kelly are pretty much done wedding planning. They are both totally on the same page, which has made things easy for them, but Megan is definitely pulling everything together and has the final say on what goes and what doesn't," the source said in July. "They are so excited to spend the rest of their lives together, traveling the world, living in complete bliss and harmony, and potentially expanding their family one day."

Check out the video below to hear more.

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