Much like Ted from the original series, Sophie serves as the narrator and lead of How I Met Your Father, telling her son the story of how his parents met. "I've been incredibly lucky in my career to play some wonderful characters and I'm looking forward to taking on the role of Sophie," Duff previously said of her casting to Deadline. "As a huge fan of How I Met Your Mother, I'm honoured and even a little nervous that Carter and Craig would trust me with the sequel of their baby. Isaac and Elizabeth are brilliant, and I can't wait to work alongside them and all of their genius."