Jennifer Garner Wishes 'Alias' Costar and Ex Michael Vartan a Happy 55th Birthday: 'XX S. Bristow'

Sydney Bristow and Michael Vaughn live on!

Jennifer Garner is wishing her former boyfriend and costar Michael Vartan a happy 55th birthday!

“I can’t remember why I was Bavarian, but I do know today is your birthday. I hope it’s a great one, Michael! XX S. Bristow,” the 13 Going on 30 actress, 51, captioned a cute throwback photo of herself and the Monster-in-Law actor on Monday.

In the Instagram upload, Garner was dressed in traditional German clothing as she held a broken beer mug.

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The pair had an on-screen romance in the early 2000s action thriller and science fiction series Alias. Garner starred as Sydney Bristow while Vartan portrayed Michael Vaughn. Their relationship carried over into the real world as they publicly dated briefly between 2003 and 2004.

Garner and Vartan have remained close over the years.

In 2018, she also celebrated his 50th birthday with another throwback of the two in their younger days.

“Can you believe this baby face is 50?!” she captioned the Instagram photo. “Happy birthday, #MichaelVartan,” she continued, adding the hashtags “#alwaysanALIASgirl” and “#sydneyandvaughnforever.”

When Garner joined TikTok in October 2021, she did it with the help of her former Alias cast members, including Vartan. Merrin Dungey, Kevin Weisman, Gina Torres, Mia Maestro and Victor Garber were also present to mark the 20-year anniversary of the popular ABC spy series.

Garner included then and now photos of her costars among clips from the reunion party.

"We're here, we're older, but we still got it," Garner wrote in the caption, adding the hashtags #FirstTikTok and #Alias20.

Related: Jennifer Garner Says She 'Couldn't Stop Smiling' While Working with 'Alias' Costar Victor Garber on New Show

When she shared the same video on Instagram, Garner praised creator J.J. Abrams for his “ambitious imagination [that] pushed every department on the crew of Alias through and past the norm, it was so much FUN.”

Garner noted that Abrams was not able to attend the reunion and that the cast “missed everyone who was working and couldn't make it in.”

As for the Elektra actress and the Never Been Kissed actor, they have both moved on.

In 2011, Vartan married Lauren Skaar, but they separated in 2014. Skaar filed for divorce in July of that year.

Garner is currently dating Cali Group CEO John Miller. Earlier this month, they were seen holding hands while on an outing in Santa Monica, California, wearing coordinating gray outfits. A source told PEOPLE in February that the pair "like to date out of the spotlight" and they are having "a lot of fun" together.

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