Jon Hamm has split from Jennifer Westfeldt after 18 years together.
The 'Mad Men' actor and his actress girlfriend have called time on their relationship but have vowed to continue to be "supportive of each other".
In a statement to UsMagazine.com, the pair said: "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, 44, met Jennifer at a party in 1997 and they began dating. However, it's claimed the pair haven't been on the same page recently.
A source said: "They've been fighting for a while, but now they're done. They decided to finally split. It's sad."
Earlier this year, Jon completed rehab for alcohol abuse ahead of the final season of critically lauded 'Mad Men'.
After finishing a 30-day stint in a treatment centre, Jon credited Jennifer, 45, with helping him overcome his addiction.
The actor's representative said at the time: "With the support of his longtime partner Jennifer Westfeldt, Jon Hamm recently completed treatment for his struggle with alcohol addiction. They have asked for privacy and sensitivity going forward."
The TV hunk and his partner previously spoke of their decision not to have children together.
In 2011, Jon said: "I have a tremendous amount of respect for my friends who do balance this particular career with raising a kid, 'cause it's a tricky environment to bring them into... So not for us just yet."