BBC America's hit sci-fi show Orphan Black returns with its final season this Saturday (10 June) and its lead actor Tatiana Maslany has already teased that the ending will not be a happy one.

Maslany spoke to US Weekly about how the show would end after season 5. She told the Magazine, "It's not a happy ending for sure, but an ending. I don't know how to say it without spoiling it."

Maslany plays the main character, Sarah Manning, alongside a number of mysterious clones who join forces to get to the bottom of their dangerous origin story. The Canadian actress has to say goodbye, not only to her co-stars but also to five clone characters she played on the show, Sarah, Cosima, Alison, Rachel and Helena.

When asked if fans will be satisfied with the ending, Maslany said, "I think what Orphan Black often does is sort of play in the gray area a lot more than in the absolutes of good and bad. What I'm always interested in are stories that challenge people. And hopefully that's what this does, whether it emotionally challenges them or mentally, or whatever, but I'm happy with how we say goodbye to the clones."

Teasing details about the final 10 episodes, the actress explained, "It's an extension of what we've been exploring all throughout, which is the sisterhood, and family, and all of those things. We definitely delve more into that, especially as this season goes on, in a deeper way than I think we have in the past. It's hard to say one way or another what the season's about, but for me, it always comes back to family."

The actress also dished on the rumours of a possible Cosima-Delphine wedding after their emotional reunion in season 4 finale. She explained, "I will let you deduce what you want to deduce from that. It's a very cool episode. I can't really say much about it but I loved shooting that episode."

"We filmed that one with Helen Shaver, who has directed a few of our episodes and she's unbelievable. She understands the love story of it but also the complications of that dynamic — Cosima and Delphine and the intimacy and the sexuality and everything," she concluded.