It’s a sad day for Hollywood!

Jon Hamm, 44, and his longtime girlfriend Jennifer Westfeldt, 45, have called it quits after 18 years together – which seems like a lifetime for famous folks.

The former couple released a joint statement saying, “With great sadness, we have decided to separate, after 18 years of love and shared history. We will continue to be supportive of each other in every way possible moving forward.”

jon hamm and jennifer westfeldt breakup

Jon and Jennifer at the ‘Girls’ Season Four Premiere in 2015.

The actors started dating in 1997 and chose not to get married.

“We may not have a piece of paper that says we’re husband and wife, but after 10 years, Jennifer is more than just a girlfriend,” Jon said in the past. “What we have is much deeper and we both know that. To me, people [should] get married when they’re ready to have kids, which I’m not ruling out.”