Looks like the gloves are now off in Hollywood's friendliest divorce.
So far, Megan Fox and Brian Austin Green have been poster children for "conscious uncoupling" as they handle the dissolution of their decade-long marriage.
But it seems a candid Instagram post from Fox flaunting her new boyfriend Machine Gun Kelly was a step too far for her ex.
She captioned the intimate photo – showing the pair wrapped in towels, her hand around his hip – "Achingly Beautiful Boy … My heart is yours."
Three hours later, Austin Green shared photos of the couple's sons Noah Shannon, 7, Bodhi Ransom, 6, and Journey River, 3. Also pictured was his eldest son Kassius, 18, who he shares with ex Vanessa Marcil.
And Austin Green's caption? "Achingly beautiful boys...... My heart is yours."
The oh-so-shady message seemed clear: Austin Green's heart belongs to his children, not his latest romantic partner. The former 90210 star's post was soon flooded with messages from celeb-watchers lapping up the drama.
"I'm here for the pettiness," wrote Perez Hilton.
"Whoa. I see what you did there," wrote one Instagram user. "Savage, love it, you're an awesome dad," said another.
Others were less impressed: "Now we know why she broke up with you. Your children must be more mature than you. Move on," was one top-rated comment.
Austin Green first announced that he and Fox had split after 10 years of marriage during a remarkably candid May episode of his podcast.
He revealed that last year "around Halloween, Thanksgiving time" Fox travelled overseas for almost six weeks to film a movie and when she returned, there was an emotional distance between them.
"I gave her a couple weeks, I figured she's been out of the country, she's jet-lagged, she's been shooting nights, I have to give her some time to recoup a little bit and get back into life, and so I did," he said.
After two weeks, nothing had changed between the pair, and Fox, 34, revealed to her husband that she'd enjoyed her time alone and even liked herself "better during that experience".
Green said he was "shocked" and "upset about it," but "wasn't upset at her".
"It wasn't a choice she made," he said. "That's the way she honestly felt."
Since the split, Fox has entered into a very public new relationship with rapper Kelly, popping up on his Instagram and even starring in one of his music videos.
Austen Green has been making headlines as well as he attempts to move on, recently spotted lunching with none other than Courtney Stodden.
Austin Green insisted he and Fox were still on very friendly terms in an interview this week.
"I think it's going as well as it can. There's no rule book to it. There's no way of doing it right or doing it wrong," he shared. "We are learning as we go. The important thing for us is just communicating as much as we can."
Even if it is via the medium of shady Instagram captions …