Even a divorce won't keep these two from putting their son first.

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On Friday, Us Weekly reported that despite filing for a divorce one month ago, Hilary Duff and Mike Comrie were able to put their differences aside for their son's birthday.

Luca turned 3 years old today and Duff took to Instagram to share the news.

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"3 years buddy! 3 beautiful years! You make every minute worth while," the star wrote.

The Younger star made sure to include Comrie in several pictures in the Flipagram and included him in the caption.

"We cherish all your firsts and all that is to come. Happy 3rd birthday my love #timesflying #whatayear."

It certainly has been an interesting year for this family of three as they prepare to live through a divorce. Duff waited one year before filing for divorce from her estranged husband, but after he was caught having a wild night out, she finally did it.

The star opened up in the April issue of Cosmopolitan about finding love and what her outlook on it is, post-divorce.

"I don't want to sound bitter because I'm definitely not, but I don't know if people are meant to be together forever. Things happen over a long relationship that you can't always fight," she said. "A marriage of 20 years, the accomplishment of that must feel really great, but there are also huge sacrifices. I just always want to fight for happiness."

As she divorces Comrie, she is allegedly fighting for primary custody of Luca.

TMZ reported that the actress and singer 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.

Tags: Hilary Duff Mike Comrie