'Grey's Anatomy' actor on Patrick Dempsey's return to the show: 'You have not seen the last of him'

He also spoke about who knew Dempsey was returning.

"Grey's Anatomy" fans haven't seen the last of McDreamy.

After Patrick Dempsey's character, Derek Shepherd, shocked fans with an unexpected return during season 17 of the medical drama, fellow "Grey's" star Kevin McKidd said there is much more to come.

"All I can say is you have not seen the last of him," McKidd, who is known for playing Owen Hunt, said when asked by ET if Dempsey, whose Shepherd character is often referred to as "McDreamy," would make any future appearances. "That's what I will say and whatever does come ... What you saw last week that everybody freaked out about is just ... the tip of the iceberg of what's to come. You'll have to watch."

"Grey's Anatomy" first introduced Dempsey's character in the pilot episode and remained on the show until he was dramatically killed in season 11.

Much like fans, McKidd shared that he was surprised by the emotional return, but was worried that the secret would be ruined.

"We were on the beach shooting this, and at one point, we saw this boat out on the horizon and it stayed there for a bit too long. We were all like, 'That's a paparazzi boat! That's a paparazzi boat!' But luckily it wasn't a paparazzi boat, but we really thought it was. There was a lot of paranoia about keeping this thing secret. It was stressful," he said. "We had to lock down that whole beach, so nobody was allowed on it. It was a whole production, like a military operation."

McKidd also said that keeping the actors in the dark prevented show leaks.

"They kept it a secret from us for a long time," he said. "That's probably why it stayed a secret because they didn't tell the actors for a long time."