Shonda Rhimes: 'Grey's Anatomy' Will End When 'We've Done What We Needed to Do' (Exclusive)

The 'Queen Charlotte' creator talks to ET about when she thinks it'll be time to hang up the doctor's coat.

As Grey's Anatomy gears up for its 20th season, speculation continues on when TV's longest-running primetime medical drama will hang up the stethoscope. Series creator Shonda Rhimes, who oversaw the early seasons of Grey's, maintains that nothing has changed when it comes to her stance on if and when the show should sign off. Rhimes and longtime star Ellen Pompeo, who left Grey's full-time earlier this season, have said over the years that it'll be time to end the show when they both decide to.

"My involvement stands in the exact same place it has always been," Rhimes told ET's Deidre Behar while promoting the launch of Netflix's Queen Charlotte: A Bridgerton Story, which drops Thursday.

"Ellen's spectacular and I think she deserves a little bit of creative time that's different from what she's been doing," she explained. "She's been doing this job -- I mean, nobody expected the show to go this many seasons. We're entering the 20th season, so she deserves the break and get the chance to do something else."

Rhimes stepped away from day-to-day duties on Grey's several years ago, handing it off to showrunner Krista Vernoff, who herself will be leaving the post at the end of season 19. She kept the door open for Pompeo, who is slated to return once more on the current season of Grey's, should she decide to put on the doctor's coat again.

"And if she wants to come back, she comes back," the mega-producer said.

Liliane Lathan/ABC

Rhimes admits she's given up on planning potential endings for Grey's now that it's continued on for nearly two decades. She confirmed she has no idea how the show will end -- not yet anyway.

"I knew how that story will end when we were in season 6, in season 7 and maybe season 10, and after that I just gave up because I would write those endings and the show just kept going," Rhimes said. "I’ll have a feeling the same way I knew Scandal [was going to end]. I'll have a feeling of like, 'We've done what we needed to do here.'"

As for what's next on her TV bucket list? Possibly exploring the sci-fi genre.

"Maybe sci-fi because I'm very into sci-fi and I'd like to do it in a way that feels accessible, and people really enjoy it because that's the kind of viewer I am," Rhimes said, confessing her worries of even tackling the space "because sci-fi is very specific and it's a pretty hard genre to crack."

If anything were to come to fruition though, Rhimes has a Rolodex of actors from projects past and present she'd reach out to: "I would attach any of the actors I've worked with before to it."

Grey's Anatomy returns Thursday, May 4 at 9 p.m. ET/PT on ABC.