The iconic role ended up going to Patrick Dempsey.
Rob Lowe was almost Dr. Derek Shepherd.
During a recent episode of WTF With Marc Maron, the 55-year-old actor joked about turning down the iconic Grey's Anatomy role that Patrick Dempsey went on to play. Lowe initially revealed that he passed on the part in his 2014 memoir, Love Life.
The conversation began when Lowe shared that he frequently turns downs roles, which led him to exclaim, "Dude, I turned down Grey's Anatomy."
"That probably cost me $70 million," he quipped. "Eh, it's just money."
There are no regrets for Lowe, though, who went on to star in shows including Parks and Recreation, Brothers and Sisters and The Grinder. "I watched it when it came out, and when they started calling the handsome doctor 'McDreamy,' I was like, 'Yeah, that's not for me,'" he recalled.
In his memoir, Lowe revealed that he was deciding between the Grey's role and one on Dr. Vegas. He ended up choosing the latter, which only aired five episodes in 2004. Meanwhile, Grey's Anatomy is currently airing its 15th season, though Dempsey departed the show during season 11 in 2015.
"After a week of negotiating, my deal was done, although not yet signed," he wrote of his role of Dr. Billy Grant in Dr. Vegas. "It was then that I got an urgent call from the producers of a potential new show for ABC called Grey's Anatomy."
"I agreed to meet with the people making Grey's Anatomy," Lowe continued. "I had read it and loved it -- the writing was crisp, real and very entertaining -- and it's always been a good idea to hear out talented people."
While he wrote that he was offered the part of Derek right away, he was "torn" over whether or not to accept the role.
"Grey's was a much better script; in fact, there was no comparison," he admitted. "[But] year after year after year, all of ABC's new dramas flopped. CBS was on a hot streak that continues to this day. Although Grey's was a much better script, I chose Dr. Vegas. The odds were just too stacked."
When ET's Katie Krause caught up with Dempsey last October, he was certainly pleased to have had the role of McDreamy, and gushed about being "a part of television history."
"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 and to really be a strong part of so many people's lives," he said at the time. "... It's really remarkable."
"... The show has been on for 15 years, which is remarkable and they are beginning their season right now, and I wish them a lot of luck and continued success," Dempsey added. "I learned a lot from my experiences on Grey's."
Grey's Anatomy airs Thursdays on ABC.