Victor Garber and Jennifer Garner (who co-starred on the television show "Alias") pose at The Roundabout Theatre Company's 2015 Spring Gala at the Grand Ballroom of The Waldorf Astoria on March 2, 2015 in New York City

Jennifer Garner is celebrating her Alias costar Victor Garber!

The Yes Day actress, 51, posted a sweet tribute to her former costar and onscreen father Garber on Instagram Saturday, as the actor rang in his 75th birthday.

“Everything’s better when I’m next to you, Spy Daddy. Happy Birthday, @therealvictorgarber! 🎈♥,” Garner wrote, sharing photos of herself and Garber.

In a first image, the pair posed for a montage of black-and-white shots that showed them laughing and chatting together. In one of the shots, Garner fondly rested her head on Garber’s shoulder.

Victor Garber and Jennifer Garner

Garner shared a photo of her on set of ‘Alias’ with her former costar Garber in a birthday tribute post to the actor on Saturday.JENNIFER GARNER/INSTAGRAM

A follow-up photo showed the actors posing together as Garner sat in an armchair, while Garber stood behind her. Next, the former costars were seen in another throwback image in a joint selfie, which appeared to have been taken on the set of Alias.

Garner starred opposite Garber in the ABC spy drama Alias from 2001 to 2006. The pair have remained close friends over the years.

Back in January, Garner had an Alias reunion with Garber and another costar on the show, Ron Rifkin, in New York City.

ALIAS - "Prophet Five"

Garber played Garner’s father on ‘Alias’ from 2001 to 2006.CRAIG SJODIN/DISNEY GENERAL ENTERTAINMENT CONTENT VIA GETTY

Sharing a photo of their meet-up at the time, Garner wrote in her caption, “NYC doesn’t happen if I don’t get a moment with my best guys, Ron and Victor. ♥️.”

In the snap, the trio smiled as they posed outside together while bundled up against the winter cold. Rifkin, 84, stood in the center wearing a bright yellow jacket and an orange scarf, while Garner stood to the left with her arm on his shoulder. Garber, meanwhile, stood to the right.

Previously in September, Garner shared on Instagram that she met up with Garber after watching him perform in the Off-Broadway play Love Letters.

“If you are my person and you are on stage I’ll do what I can to see you. ♥️ @therealvictorgarber is my person,” she wrote alongside a photo of her and Garber at the Irish Repertory Theatre in Manhattan. “And on stage with incredible [J. Smith Cameron] =⭐️♥️👏.”

Garber reposted the photo, writing in his own caption: “Last night a surprise visit at Irish Rep Theatre. Today is the last performance for me and J. Smith Cameron. Thank you Irish Rep for this wonderful opportunity. XX.”