They were one of the most enduring relationships in Hollywood, but sadly Jon Hamm and Jennifer Westfeldt have broken up after 18 years together.

The much-talked about relationship had been the subject of rumors of rough times for a while now, but it was only on Monday that they confirmed the split.

"With great sadness, we have decided to separate, after 18 years of love and shared history," the couple told People in a statement.

jon hamm jennifer westfeldt

"We will continue to be supportive of each other in every way possible moving forward."

Jon, 44, and Jennifer, 45, were a frequently asked about the union after Jon shot to fame as Don Draper on Mad Men, usually speaking lovingly about each other and how the two never felt the need to get married.

“We have always felt married,” Jennifer told In Touch in 2010. “We just had our 12-year anniversary last week, and we have a house and a dog! At some point we may, but it doesn’t matter to us one way or the other.”