The actor announced his engagement to Kelly Gale on Monday.
The 40-year-old actress took to the comments section of Kinnaman's announcement post on Instagram to share some love, simply writing, "💯💯💯💯."
Kinnaman's post featured himself down on one knee popping the question to his grinning 25-year-old fiancée.
"She said no. Jus kidding...," the 41-year-old Suicide Squad star captioned the pic.
Munn and Kinnamon dated for two years, splitting up in early 2014. She went on to have romances with Aaron Rodgers and Tucker Roberts, whom she split from in late 2019.
Kinnamen and Gale went public with their romance at Coachella in April 2019. This will be the first marriage for Gale and second for Kinnaman, who was married to Swedish tattoo artist Cleo Wattenström from 2015 to 2018.
As for Munn, in 2019, while still dating Roberts, the actress didn't commit to the idea of marriage for herself.
"I've really come to a realization with myself that I'm already in my happily ever after," she told ET. "And if I want to have kids or want to get married then I'll do that, but it has to add to my life, you know? Everything has to add to my life."