Brian Austin Green Seemingly Reacts to Megan Fox Calling Machine Gun Kelly Her 'Achingly Beautiful Boy'

The post-split shenanigans between Brian Austin Green and Megan Fox just reached a new level of awkward thanks to a pair of new Instagram posts.

On Wednesday, Fox posted a selfie with new boyfriend Machine Gun Kelly on her page (above). Aside from a previous clip from her appearance in his "Bloody Valentine" music video, this is the first time he's popped up on her feed.

She captioned the image, which shows her in a bikini and him shirtless, "Achingly Beautiful Boy ... My heart is yours."

Remember that caption, as her ex, Green, appeared to troll her comment with a series of photos on his own page.

He posted four photos, highlighting his four children. His caption: "Achingly beautiful boys...... My heart is yours." Insert side-eye emoji here.

In his comments, some fans replied by shading Green. "Someone mad .. .Kells would whoop that ass old man," wrote one. Another added, "Now we know why she broke up with you. Your children must be more mature than you. Move on."

Green responded to both comments with a 😂  emoji.

Green and Fox share three kids; Noah, 7, Bodhi, 6, and Journey, 4. He also shares son Kassius, 18, with ex Vanessa Marcil.

The "90210" star has been sharing a lot of photos of his, until now, rarely-seen children -- something he admitted was recent fling Tina Louise's idea.

Speaking with Hollywood Raw with Dax Holt and Adam Glyn, he said he's been posting more to reclaim the narrative about him in the media, using it to shift focus from his love life to how he's been spending time with his four children.

The only time Green was a little cagey with his answers during that same interview came when he was asked how he found out Fox was dating the rapper.

"I found out in my own way. And that's as much detail as I'll give you on that one," he said, simply adding that he, "didn't read about it or anything like that."

As for Megan, Green said things between them are "going as well as [they] can."

"There's no rule book to it. There's no way of doing it right or doing it wrong. We're learning as we go. The important thing for us is just communicating as much as we can," he said. "I think for us, the realization that we can't take the view that it won't affect the kids, because it will. I think it's up to us, and parents in general, how it affects your kids. Whether it's a really negative experience for them or it's okay and they feel safe in it and they feel loved and everyone still loves and respects everyone, things are just different. It's not bad different, it's just different."

"I wish Megan the absolute best in everything. I want her to be completely happy, for her and for the kids. That's super important," he said. "Nobody wants to be around somebody that's unhappy, nothing good comes out of that. That's a terrible situation. We are taking it day by day."

He went on to defend Fox, saying she's been criticized for being in Mexico filming a new movie and spending time away from their children during the pandemic.

"Everybody is judgmental right now because she's out of the country working and she's not around. They're trying to say, 'What about the kids?'" he said.

"This is what we do. We travel and we work. It's no different now than it's before, except that we're just no longer together. This is what we've been doing for 15 years," he added. "When one person is traveling and working, the other one will step in and take care of things at home and the kids and this situation is no different. It's not for lack of caring. Megan loves her kids and would do anything for them, and has and will continue to."