Grey's Anatomy star James Pickens Jr. talks Richard's diagnosis

Warning: This article contains spoilers from the season 16 finale of Grey's Anatomy.

What's wrong with Richard Webber? That was the question everyone was asking going into the season 16 finale of Grey's Anatomy. Was it Alzheimer's? Was it some mysterious illness we'd never heard of before?

In the end, it was the latter: Thanks to a hip replacement he got a few years ago, Richard (James Pickens Jr.) was suffering from cobalt poisoning, a mystery solved by none other than DeLuca (Giacomo Gianniotti), a man in desperate need of a win. And in more good news, it was revealed that all Richard's symptoms could be reversed.

EW spoke with Pickens, who's been playing Dr. Webber since the show's pilot, about his latest story line and more.

ENTERTAINMENT WEEKLY: When a story this big is coming for your character, do you get a heads-up or do you find out when you read the script?

JAMES PICKENS JR.: They did give me a heads-up that they had some ideas in terms of my character, and the direction it was going to take. They had already kind of set some things up with he and Catherine [Debbie Allen] now at odds and them separated from one another. So he was dealing with a myriad of different things there in his life. When Krista [Vernoff, showrunner] said, "Well, we've got this story line, we think it's going to be really interesting," I listened and said, "Oh, okay, go for it." I have to say that Krista and the writing team have been pretty amazing over the years, especially with my story line with a quote-unquote 'mature' actor, to still write some really great and engaging stuff for him. I'm feeling pretty lucky about that. It was nice to play, too. Fans got a chance to see another side [of Richard] and see that he's as human as the rest of them.

Did you know it was cobalt poisoning, or was it a bit of a mystery to you as well?

They did tell me that it was cobalt poison, which I knew nothing about. And it was such a specific issue. I did a little research and thought there's a lot of layers you can play, physical and emotional. And it is somewhat common, so yeah, it gave me something nice to kind of reach for.

Have all of the crazy plot twists over the years been a central component in keeping you interested in playing the same character for so long?

Oh yeah, absolutely. I've been really lucky in that sense, that over these past 16 seasons I've gotten a good share of some really interesting story lines and interactions with interns and attendings and my personal life, whether it be Adele or, early on, Ellis, and now Catherine. It's kept me engaged as an actor. And then, I think just by the nature of the show, it's something that I look forward to every time we read a new episode.

What are the twists that stand out to you over the years, the stories that really challenged you as an actor?

There have been a couple. Obviously, the alcoholism. That was really something that was kind of cathartic for me on a personal level. My dad struggled with alcoholism toward the end of his life, so I got to watch him struggle, and he battled it valiantly. I think the thing that I was most proud of was the fact that that story line helped me to understand what that day-to-day struggle was like. I had quite a few people come up to me in the past who were recovering, and they said how much that story line really helped them to work through some things themselves, but also recognize that this is an issue that is quite common. And then there was a flashback episode, which was basically about my mother. About three or four seasons ago, we flash back to his mother and his two younger siblings, and that was a tough one for me, because it really mirrored my early life. I lost my mother at a young age, and I had two younger siblings, and it was so close to that. That one was harder to get through, but in a way it was also very cleansing for me to do that. So there've been a few of them, but those two stick out for me. And this one now, absolutely.

Did they let you know going into the cobalt poisoning story that Richard would be okay?

Yeah, they did. Look, I've been doing this a long, long time. And you know that nothing is guaranteed in this business, whether you've been with it for one season or 16. I take nothing for granted. So I didn't go out and say, "Hey, am I going to be okay here?" But they let me know right off. They said, "Don't worry, you're going to be fine." I said, "Okay."

Related content:

• Grey's Anatomy boss on how season 16's early finale affects certain stories
• Grey's Anatomy season to end early with episode 21 serving as the finale
• Grey's Anatomy cast thanks doctors for their work on National Doctor's Day