Patrick Dempsey, wife Jillian celebrate 18th wedding anniversary

Aug. 1 (UPI) -- Patrick Dempsey and his wife celebrated 18 years of marriage this week.

The 51-year-old actor and wife Jillian Dempsey rang in the occasion Monday following their months-long split in 2015.

"Happy 18th anniversary @patrickdempsey! Through thick and thin....I love you ~ wifey," Jillian captioned a photo on Instagram of herself with Dempsey.

Dempsey and Jillian reconciled in fall 2015 after Jillian filed for divorce in January that year. The actor, who shares 15-year-old daughter Talula and 10-year-old twin sons Darby and Sullivan with his wife, explained their reunion in September.

"Jill and I decided it was time to work on our issues and improve," he shared in the Sept. 19 issue of People. "We wanted to be role models for our kids, like, 'Okay, if you have differences, you can work them out.'"

"I [learned] to prioritize," the star said of his renewed focus on family. "Our union has to be the priority. I wasn't prepared to give up on her and she wasn't either. We both wanted to fight for it."

Dempsey is known for playing Derek "McDreamy" Shepherd on Grey's Anatomy, and has since starred in the movie Bridget Jones's Baby. He is slated to direct and star in a segment of the new film Berlin, I Love You.