Thirteen seasons in, ABC's Grey's Anatomy is showing no signs of slowing down, and that is just fine with leading lady Ellen Pompeo (Meredith).

The actress, who signed a new deal to return for season 13, tells THR that she isn't taking the show's success lightly — and that there are no plans to hang up the proverbial scrubs anytime soon given its new ranking as ABC's No. 1 drama.

Additionally, the actress opens up about the show's continued reinvention as castmembers (think Sandra Oh and Patrick Dempsey, among others) come and go.

This season focuses on the original stars — you, Justin Chambers, Chandra Wilson and James Pickens Jr. What does that mean for Meredith and her journey this season?

It's strange because when we've lost people from the show, you feel sad and you feel like, "Is it going to be the same? Is it going to be more fun?" But in a funny way, the evolution really helps us continue. And we're finding our way. The writers are doing a great job. I don't know what it is, but we're having a great time. I think we're all in a place — Justin, myself, [creator] Shonda Rhimes, Jim Pickens, Chandra Wilson — all the originals that are left. You go through a journey of 13 years and at this stage, you're just so grateful that we've had the support that we've had. I mean, can you imagine the audience has supported us for 13 years? Some movie stars don't get a career that long. And we're on every week, and people are still watching. We don't take it lightly. It's unbelievable.

From what we've seen in the season-13 premiere, Meredith is getting a lot of time early on with Alex.

Justin and I have such unbelievable chemistry. I would sit on the sidewalk with him for days and I wouldn't have to do anything. He's one of my closest friends. So to be able to get to act with him and to have stories that we get together all the time is a dream come true.

How will Alex's arrest impact his reputation and the season going forward?

He's going to get demoted at work. Justin is an unbelievable talent. He's just so simple and present, and he's an amazing scene partner. I always say I've never had a scene partner like Sandra Oh; she was the most incredible scene partner. And Justin is right up there with her. I'm having a ball with him this season. All we have to do is look at each other and we really vibe.

Meredith also told Riggs (Martin Henderson) that she isn't interested in him, though it seems pretty clear she's just being a good sister.

Yes! Well, apparently they've had sex several times in a car — which is not something I can condone or advocate. I think a hotel or a bed possibly would have been better. But Meredith continues to make bad choices as a parent. [Laughs.] It has been revealed that Maggie (Kelly McCreary) has a crush on Riggs too, so it's a good way out for Meredith because she doesn't have to commit and can't have anything to do with him. She has a good excuse to not feel guilty about her dead husband (Dempsey's Derek) because her sister likes him.

Is she inching toward being ready to date again?

She is inching. But there are 24 episodes, so we have to inch forward, inch back. But that is a fun triangle to play.

Grey's is ABC's top drama in season 13, an impressive accomplishment. Do you and Shonda have an end game?

We're blessed to be able to go on this long. As long as the show is successful and Shonda and I and the cast are having fun, I think that will be a decision that Shonda and I come to. Obviously the network and the studio will have some say. There's no talk of going away with numbers like this. As long as the show's a success — I mean, it's so fun! It's such rarified air. To have a show on the air for this long and have it be this successful and have it be driving a whole night of television and be the network's No. 1 show — I'm super grateful. And I don't want to take that for granted, and I don't want to walk away from the golden goose. I want to put a leash around it and take it everywhere with me.

Grey's Anatomy airs Thursdays at 8 p.m. on ABC. Pompeo is a partner with Philosophy's #CoolAger campaign, which honors the Aviva Community Fund.