'Grey's Anatomy': Camilla Luddington and Chris Carmack on Season 18 and Kate Walsh's Return (Exclusive)

The new season kicks off Thursday.

Grey's Anatomy is gearing up for another monumental season. After a slew of familiar faces returned last year, season 18 will be welcoming back even more beloved characters:, including Kate Walsh, who played Addison Montgomery, and will be recurring for several episodes.

"First off she is amazing," Camilla Luddington told ET's Katie Krause recently, admitting that she didn't know Walsh was coming back until she read the script. 

Her co-star, Chris Carmack, also wasn't aware of Walsh's return until he received the script: "And then [I] saw her at the Zoom table read." 

"He geeked out. Everyone geeked out basically," Luddington recalled. "She is back and it is kind of like she's never left before. I feel like her presence in scenes is that she kind of owns the hospital. I am like, 'Oh my god, it is Addison.' But I think we can say that she is working on a really amazing case that Jo is desperate to get in on. It's always possible there is drama."

For Jo, she's about to embark on a new journey after finding her calling and expressing her desire to become an OBGYN at Grey Sloan. That, and she's raising a baby alone. 

"A couple of things are happening for her. She has a new baby so she is dealing with a single-working mom and not having much help and I think that that is really good for... she is leaning on Link for advice, which is her bestie, on how to do this and then what you are going to see that is kind of fun, which it didn't even really occur to me until this season is that she is back to being an intern," Luddington said with a laugh. "She is back to square one so she is doing scut and I feel like that energy in the early seasons of her being an intern and making mistakes and running around is back again for her so it has been really fun to play."

As for Link, he's going to be dealing with the fallout from Amelia turning down his marriage proposal. At the start of the new season, the pair go to therapy to air out their dirty laundry and maybe find a way to resolve their relationship issues.

"He definitely got turned down in a big way... multiple times," Carmack said. "I am reading the script and I am going, 'Link, are you sure you want to do this?' But he swung big. He got the kids in there. He got four rings. He was ready and she turned him down spectacularly and it definitely threw him for a loop because he started thinking about marriage differently when he was living with Amelia because he was not sold on it first. But then he just fell head over heels for her and he said, 'This is the woman that I want to spend the rest of my life with. Now he seems to have equated marriage with the only thing that that can be possible and he is pushing real hard for it and the rejection was a lot so he is crawling back into his hole and trying to recover. Meanwhile, he co-parents Scout with Amelia and having to coexist with her in that world and it's a little bit of friction."

The early promos for the upcoming season appears to put Meredith in a different, reinvigorated mindset following her trying experience with COVID-19. That experience, along with the return of her late mother Ellis Grey (played by Kate Burton), will reshape her priorities in season 18.

"It is like her eighth near-death experience," Luddington said. "It made her focus on what matters to her and all of these things that don't necessarily matter in her life and streamlined her into thinking more about future big decisions for herself." 

"She is cutting out some of the fat or some of the BS in her life and really making important decisions for herself," Carmack echoed.

And there could be an O.C. reunion for Carmack with new guest star Peter Gallagher, who joins the season as a doctor who had ties to Meredith's mother. Though they haven't shared any scenes together yet or crossed paths on set, Carmack is hopeful there will be a time when that day comes.

"I'm really hoping we get to work together because it's great seeing him in the table reads and he's a sweetheart and I can't wait to work with him again," he said. 

Luddington, meanwhile, expressed her personal wish to have former Grey's star Jessica Capshaw back in the fray one last time. 

"I was speaking to Capshaw yesterday and I would love to see Arizona come back. I just adore her. I think the character is amazing, I think Jessica is amazing. I would love for her to come back and work with Jo now that Jo's OB," the actress expressed. "That would be my pick."

The premiere, which is part of a two-hour crossover event with Station 19, follows the Phoenix Fair in Seattle. "There's a big fair happening in Seattle, Grey's is short-staffed and I feel like there's a little bit of everything in the premiere," Luddington previewed. "Our writers are amazing, they're able to fit everything in -- a little bit of drama, a little bit of relationships, a lot of Meredith. Cool, interesting things are happening in the premiere."

"Amelia and Link come together in the first episode, working together on a medical case and they have to put all of their personal stuff behind them," Carmack teased. "Meanwhile, there's a lot of personal stuff happening in front of them with the patient that is reflecting what is going on with them. So it's like they're not talking about it, but the patients are talking about it. It's a very funny dynamic.

Grey's Anatomy premieres Thursday, Sept. 30 at 9 p.m. ET/PT on ABC. For more, watch below.

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