The 47-year-old shared a rare photo on social media over the weekend, showing himself posing surrounded by his four sons.
On Sunday, Brian Austin Green posted the sweet snap proudly smiling with Journey, 4, Bodhi, 7, and Noah, 8 -- whom he shares with Fox -- and Kassius, 19 -- from his relationship with actress Vanessa Marcil.
The Beverly Hills, 90210 actor beamed with happiness while soaking up the sunshine with his kids at his Malibu, CA home.
Battling the SoCal heat, Brian Austin Green and his boys took a dip in the pool for their afternoon father/son playdate.
"Happy Father’s Day everyone!!!" he wrote, before praising his girlfriend Sharna Burgess for capturing the special moment.
"Thank you baby for taking such an amazing pic for me," he added.
When Sharna replied, "Happy Father’s day baby. You’re amazing," his followers immediately sounded off on his soon-to-be ex-wife.
"Yes he is you never see his x taking care of those kids they are all so gorgeous god bless you," one follower wrote. "I’m no fan of his ex but just bc she doesn’t post her kids doesn’t mean she isn’t taking care of them. There is life outside what you post," commented another.
Meanwhile, Megan stayed silent on Father's Day, not even giving her ex a nod.
Over the weekend, the Transformers actress was spotted buddying up to Kourtney Kardashian.
Fox and the Keeping Up With The Kardashians star was seen laughing and rocking out to their boyfriends, musicians Machine Gun Kelly and Travis Barker.
The duo looked like the ultimate fangirls while supporting MGK during his secret rooftop show in Venice. Barker plays drums in the band.
Fox even played stepmom for the day to MGK's 11-year-old daughter, Casie Colson Baker.
The actress held hands with the rocker, who was photographed with his arm around his child.
Brian Austin Green was the furthest thing from Fox's mind over the weekend.
This isn't the only time the exes have gone to blows over their children spending time with Dad.
In October, Fox accused the actor of "using" their kids on social media to make her look like a bad mother.