The 52-year-old actor reflected on his "magic" connection with Pompeo, his former co-star on the ABC series, in an interview with Entertainment Tonight published Thursday.
"That was a very special bond that just -- there was a magic to our connection and that's special," Dempsey told the publication.
"I think it started with the original cast and the length that it has and the new people that have come in, and it's amazing and it's continuing to affect so many people," he said of the show. "You're a part of television history. It's really remarkable."
Dempsey played Dr. Derek Shepherd, a love interest to Meredith Grey (Pompeo), in 11 seasons of Grey's Anatomy, and was killed off in Season 11. Pompeo called Dempsey "a tough act to follow" in the Sept. 28 issue of Entertainment Weekly while discussing Meredith's lack of new love interests.
"Patrick Dempsey is a very tough act to follow, and it's challenging to get someone to come on a Season 15 show," the actress said. "We're gonna find someone who makes an impact. That's our biggest challenge this year."
"There are possibilities all around her in the hospital and in Seattle at large," showrunner Krista Vernoff added. "Dating is complicated, and you don't always fall for the first person you sit across from. We're trying to reflect some of that."
Dempsey will star in an upcoming Epix miniseries adaptation of the Joel Dicker book The Truth About the Harry Quebert Affair, in addition to a Sky Italia series adaptation of the Guido Maria Brera novel Devils.