Aisling Loftus and Gregory Fitoussi admit they are sad to be leaving Mr Selfridge, but are excited about the prospect of what they will do next.
This week viewers will see their characters, window dresser Agnes and her French husband Henri Leclair quit their jobs in the London department store and move to the countryside to start a new life, after Henri's post-traumatic stress syndrome from the First World War almost tore them apart.
Gregory said of leaving the hit ITV drama: " I feel sad because I really loved everything. I lived here, the people I've met, the life in London, and the show itself, so I'm going to be sad I'm going to miss everything."
Aisling added: "I think we both felt like our characters had come to their natural ends. I think it's really satisfying the way their story ends. It's not melodramatic, it's quite quiet, but I think the final note is, 'They're going to be alright because they really love each other, and you can get through anything if you really love someone and they love you.' Which is a lovely end to that story."
She added: "I think I'll miss the people the most. I've just been really lucky, I don't think it's common that you end up working with people that you can really call mates. I love working with Gregory, I love working with Amanda Abbington, she's probably the funniest person ever. And just everyone - it's like getting to go to work with your mates every day."
French actor Gregory, 38, is keen to do more work in Britain.
He said: "I can't say because it's not up to me, but I'd really love to. I enjoyed playing in English, and I feel able to act in English now, so I'd love to do more. That's one of the reasons I'm leaving the show is to do something different. Something else."
Aisling, 24, is not sure what she wants to do next, but she is confident she will not find herself typecast in period drama.
She said: "We were out of the corsets this series, which was nice. I don't think I've done enough to be typecast to be honest.
"I've not had a lot of life yet, so hopefully that means that I can do whatever. And I don't think I look much like Agnes when I'm walking around, so I'm not really fearful of that.
"I get recognised a bit. But it's not like Justin Bieber! It's not crazy."
She added: "Next up more than anything , rather than a certain medium, I'd love to work with the directors I admire and the writers I admire, the people that make the shows that I am a fan of, so fingers crossed."
And though their characters' story has been left open, they do not think they will be returning in the fourth series, which Andrew Davies has already begun writing.
Gregory said: "I don't think so no. For now it's over."