Hilary Duff and Mike Comrie clearly put their son before everything.

Find Out How Hilary Duff Is Taking On Life After Divorce From Mike Comrie

On Tuesday, Yahoo! Celebrity reported that despite filing for divorce recently, Comrie and Duff came together to throw their 3-year-old son, Luca, a birthday bash.

The two, known for being friendly as exes, continue to shed light on what parenting should look like in photographs captured at the party.

Hilary Duff & Mike Comrie Come Together For Son Luca's 3rd Birthday

It's only been one month since the actress filed for divorce, but it doesn't appear that either hold any resentment.

Duff's sister, Haylie, captured all of the sweet moments and shared them on Instagram.

The first photo shared from the party features the sisters eating cupcakes at the party with the caption: "Going hard for Luca's 3rd birthday."

The most revealing photo of all was when Haylie Duff shared a snap of two guys carrying the cupcake-pull-apart-cake. Of course, one was her soon-to-be-ex-brother-in-law, Comrie.

He was seen holding the cake and smiling at the camera as Haylie shared her sweet caption: "Cutest Dad-to-be and Dad around!"

TMZ reported that Duff wants full custody of her son, Luca, and wants Comrie to have visitation but is worried that his partying and drinking may interfere with his well-being and could adversely affect their son.

The former couple reportedly signed a prenup when they wed, but neither are struggling with finances. Duff allegedly just wants to make sure her earnings and possessions remain hers.

The two married in 2010 and when they separated, Duff's mom, Susan, reportedly said, "They're better friends than a married couple."

The two, though divorcing, will likely remain civil for Luca.

"We're constantly seen together and people are like, 'What are they doing? Are they back together? Are they not?' We're really good friends and we have so much respect for each other and obviously Luca is our No. 1 priority," Duff told E! News.