The gorgeous pair originally met in 2015 while the 34-year-old starred on the Hollywood hunk's hit series Mad Men. Hamm and Osceola did not take their relationship to the next level until 2020 after they were spotted out together multiple times.
The soon-to-be-married couple have kept their relationship out of the public eye for the most part, but stepped out together on a few occasions at a 2022 Oscars after-party, the launch of the Sarah Silverman musical Bedwetter, the ESPY Awards and for the world premiere of their movie together.
"This is all part of what I'm saying. This is another place in my life that I feel very settled and comfortable. I'm in a relationship right now and it's comfortable," he told the shock jock, seemingly referring to his bride-to-be.
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"It's only been in the last couple of years, me kind of sitting down and thinking about all that stuff, that's made the relationship that I'm in now even more meaningful and opened up the possibility of things like being married, having kids, defining a new version of happiness, life, wellness," the 51-year-old noted. "It sounds hokey and whatever, but it's real and for one of a better word, it's what I'm working for. What else is there other than that?"
When Stern asked how he felt about Osceola, he added he was "very much so" in love.
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Hamm previously dated actress Jennifer Westfeldt for 18 years but split in 2015. Luckily, for both parties, the break up was mutual. "We will continue to be supportive of each other in every way possible moving forward,” they said in a statement.
People confirmed the news of Hamm and Osceola's engagement.