Jennifer Westfeldt has been Jon Hamm’s greatest supporter after completing a stint in rehab for alcohol addiction.

As the longtime girlfriend of the Mad Men star, Jennifer Westfeldt knows better than anyone the struggles that have plagued Jon Hamm through the years.

According to a source for People magazine, Jennifer Westfeldt, 45, has also helped “keep him in line.”

“He needs [Jennifer],” said the source. “He has to have that in his life.”

The source of many of Jon Hamm’s struggles stem from the loss of his parents, who divorced when he was a toddler.

His mother died when he was only 10 and his father when he was 20.

“He lost his mother at a really young age and grew up without that type of figure in his life,” said the source.

Inside Jon Hamm's private struggle http://t.co/sfTPAXxuJg pic.twitter.com/YwMcxbBH1m

— People magazine (@people) March 25, 2015

In 2010, Jon Hamm opened up about the loss of his father.

“I was … unmoored by that,” he told The Observer about his father’s death. Left “in bad shape,” Hamm turned to therapy and antidepressants to beat the illness.

“It gives you another perspective when you are so lost in your own spiral,” he said. “It helps.”

PHOTO: Jon Hamm, after completing a 30-day stint in rehab, arrives at the #MadMen final premiere on Wednesday pic.twitter.com/APka9rVWbV

— Variety (@Variety) March 26, 2015

Jennifer Westfeldt claims the dark character Jon Hamm plays on Mad Men, Don Draper, has affected real life.

“It’s a confusing juxtaposition,” Jennifer Westfeldt told GQ in the magazine’s latest cover story, which features Hamm. “I think the darkness of Don has weighed heavily on Jon, despite it being the role of a lifetime and the opportunity that gave him the career of his dreams.”

#Breaking: Jon Hamm completes rehab stint for alcohol, just days before #MadMen's final season http://t.co/lphmxS3KPV pic.twitter.com/n1TgW4GwHv

— TMZ (@TMZ) March 25, 2015

Mad Men‘s seventh season concludes April 5 on AMC.