Anyone who has learned about Megan Fox and Machine Gun Kelly's whirlwind romance is undoubtedly still stunned by the idea. After all, the Jennifer's Body star had only separated from her husband Brian Austin Green late last year and had always been very private about her life.

Not surprisingly, her ex isn't pleased with the way Fox has been flaunting her relationship with the rapper. Green had reportedly claimed to be "annoyed" with the way his ex-wife is being very public about her affair with Kelly.

Brian Austin Green recently threw some shade at Megan Fox when he posted photos of his sons on his official Instagram account. He then captioned the post with, "Achingly beautiful boys...... My heart is yours." The caption was clearly a reference to Fox's own Instagram post that showed her with her new boyfriend Machine Gun Kelly.

Needless to say, people were not surprised that Green was throwing shade at Fox considering that he has been taking care of their three sons since they separated late last year.

Interestingly, a source close to Brian Austin Green has confirmed that the 90210 star's actions revealed how he truly felt about Megan Fox's decision. "Brian is annoyed that she is so focused on her relationship with Machine Gun Kelly," the 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 also stated that Brian Austin Green is having a hard time understanding why Megan Fox is acting the way she does with Machine Gun Kelly. "It definitely annoys Brian. And it stings a bit too that Megan moved on so quickly," they said. "Megan was always very private, so Brian just doesn't get what changed." 

Megan Fox and Brian Austin Green had been a couple since 2004 but the two only tied the knot in 2010. During their marriage, they had three sons Noah Shannon, who is 7, Bodhi Ransom who is now 6, and 3-year-old Journey River.

All of the boys are, currently, living with Green while Fox is working on a new movie with Machine Gun Kelly. Fox and Green separated in late 2019 when the former asked for some space after working on a film overseas.

Megan Fox has yet to comment on Brian Austin Green's Instagram post. In the meantime, she is working on the new film Midnight in the Switchgrass with Machine Gun Kelly. The movie has not yet been given an official release date.