Dempsey, 54, reprised his role as Derek Shepherd, aka McDreamy, for the first time since he was dramatically killed off in a season 11 episode in April 2015.
In the waning moments of the episode, which hinted at a "shocking, jaw-dropping ending," Meredith -- who had been found unconscious in the Grey Sloan parking lot -- saw her late husband, Derek, waving at her from afar as they both stood on a sunny, nondescript beach in a dream sequence.
"Please let’s come together, respect each other, wear a mask, and thank our first responders," Dempsey wrote in his first social media post since his surprise appearance. "They work tirelessly and risk their lives to keep us safe."
"We will see more of [Derek] this season. This was not just a cameo. He will appear three more times," she said.
Pompeo and Dempsey explained how the surprise return came together, revealing that it was a hike one day near their homes after years without being in contact that planted the seed.
"The idea just struck me so I just said to him, would you ever consider coming and being a part of the storytelling this season?" Pompeo told Deadline, referencing Dempsey's cancer foundation in Maine, where he helps cancer patients and cancer survivors. "There’s just so much darkness, and we knew that coming together would be a little ray of light. And so, I think we had the same idea, at the core, to want to help people and bring a smile to people’s faces. So, he loved the idea, and we were just so excited, and we had a ball filming it."
"We hadn’t spoken or been together for a while. It was a great opportunity to catch up and say, 'OK, what can we do for all the frontline responders?'" Dempsey said. "I’ve been tracking what Grey’s had been doing with giving masks, and making sure that people had the right equipment, and it came from that place. 'OK, what can we do to make people feel better, to give some comfort in this time of uncertainty,' and that’s how it began. And it was really a wonderful experience to go back, to work with [director/EP] Debbie [Allen]."
Added Dempsey, "The whole atmosphere has changed, certainly working at the beach, and seeing everybody again was really a very healing process, and really rewarding, and a lot of fun. And hopefully, that feeling translates, and the fans enjoy it. I know that they’ve been wanting us to get back together, and I think this will satisfy a lot of people, and surprise a lot of people, hopefully."