Arnold Schwarzenegger and Maria Shriver Are All Smiles While Reuniting for Daughter Katherine"s 27th Birthday

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Arnold Schwarzenegger, Patrick Schwarzenegger, Katherine Schwarzenegger, Christina Schwarzenegger and Maria Shriver Courtesy of Katherine Schwarzenegger/Instagram

Say cake, er, cheese! Arnold Schwarzenegger and his estranged wife, Maria Shriver, reunited on Tuesday, December 13, to celebrate their daughter Katherines birthday, and looked happier than ever.

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"This is 27!" the birthday girl captioned a family photo on Instagram with her two parents and her younger siblings Christina, 25, and Patrick, 23. "Thank you to my amazing family and my fabulous friends for making this birthday one for the books! Christopher you were missed. 27 is going to be my best year yet!"

Missing from the family photo op was the pairs youngest son, 19-year-old Christopher.

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Schwarzenegger and Shriver called it quits on their marriage after 25 years in 2011 after the former governor of California"s shocking affair with their longtime housekeeper, Mildred Baena, became public. (Schwarzenegger fathered son Joseph, 19, with Baena.)

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During an interview with Howard Stern in July, the Terminator actor, who is replacing Donald Trump as host of The Apprentice, talked candidly about his mistakes and failed marriage.

"This was without a doubt the biggest setback and the biggest failure [in my life]," schwarzenegger said while recalling their split. "Not only failure, but you really feel like, "I"m to blame for it. It was me that screwed up," and you can"t point the finger at anyone else."

Failed marriage aside, the two who have yet to formally divorce five years after separating have been co-parenting their children together since.

In May they celebrated Patricks graduation from USC, and in July they rang in Schwarzeneggers 69th birthday together.

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Source: http://www.usmagazine.com/celebrity-news/news/arnold-schwarzenegger-maria-shriver-reunite-for-daughters-birthday-w456053