Uh oh, Megan Fox and Brian Austin Green’s break-up might not be as amicable as we initially thought…

According to reports, the 47-year-old actor isn’t happy that his ex-wife (but not officially, as they haven’t got divorced yet) is flaunting her brand new relationship on social media. They were together for 15 years, before separating last year.

Megan Fox, 34, is currently dating 30-year-old rapper Machine Gun Kelly – real name Colson Baker – who she met on the set of Midnight in the Switchgrass last year.

The new couple has been posting pictures of each other on Instagram with very soppy captions, which has quite understandably “annoyed” Brian Austin Green…

“Brian is annoyed that she is so focused on her relationship with Machine Gun Kelly,” a source told People.

“He doesn’t understand the need to post social media pictures with silly captions to proclaim her love for him. They aren’t even divorced yet.”

The source added that the former 90210 star is even more annoyed because Megan Fox is usually such a private person, so the social media proclamation of love is quite out of character for her…

“It definitely annoys Brian. And it stings a bit too that Megan moved on so quickly,” the source continued.

“Megan was always very private, so Brian just doesn’t get what changed.”

Brian Austin Green previously said that he wanted Megan – who is the mother of his three sons Noah Shannon, 7, Bodhi Ransom, 6, and Journey River, 3, – to be happy, even if it wasn’t with him.

However, we think her and MGK’s over-the-top posts might be a tad too much…

Thoughts?