On Thursday, Garner shared a picture on Instagram Stories of her with Garber backstage at Broadway’s revival of Hello, Dolly!, alongside his co-star in the show, Bernadette Peters. Garber played Garner's father on Alias, which ran on ABC for five seasons, ending in 2006.
"If you want to be happy ...go see @hellodollybway!!" Garner wrote, calling Garber a "king," and Peters a "queen."
“I am finding a great joy in singing again and I’ve missed it,” he told ET. “The problem is I haven’t kept it up, but I am getting back in shape and I’m feeling really good at it.”
"Once I knew Bernadette was involved, I jumped at it and said, ‘Of course I want to do it,'" he shared. "Then I went to see the show after I said yes. It’s what you call a no-brainer.”
Garner, 45, and Garber, 68, have remained notably close over the years. Garber even married Garner and her ex-husband, Ben Affleck, in a private ceremony on Turks and Caicos in June 2005.
Garber appeared on Watch What Happens Live With Andy Cohen earlier this month, when he talked about how Garner has been doing since her split from Affleck in 2015 after a decade of marriage.
"She's doing really well," he said. "Her children are great, and she's working, and she's extraordinary."
ET recently spoke to Garner as well as Josh Duhamel about their new film, Love, Simon, in which they play parents to a closeted teenager named Simon. The two talked about laughing off dating rumors that inevitably sprung up between the two given their high-profile breakups -- Duhamel split from singer Fergie last September after eight years of marriage.