Casting director Marnie Saitta only told Durant the role was a Claire recast after the actress got the job. Durant made the conscious choice not to watch Keegan's performances and instead rely on speaking to cast members and studying history to make Claire her own. She shared:
It’s a tough call as an actor because it can be a vicious trap. Olivia is Olivia and she’s brilliant. I sort of made the call that I would just listen to what people said. I would listen to how the character was and just do my best to find it within myself as the weeks went on. It was a welcome challenge and I feel like I was very supported before we shut down.
She learned about Claire and her family relationships by working with her co-stars, saying:
I just remember watching them work and just studying them because it’s such a well-oiled machine and I think those iconic people that have been there for so long have it down to a T. The professionalism and the kindness and generosity you have when you’re in their presence was really special to me. I sort of looked up to them and I knew that I could ask them any questions.