(Cover) - EN Showbiz - Kristen Stewart was shocked by her character's steamy sex scene in The Twilight Saga: Breaking Dawn Part 1.

The American actress stars as Bella Swan in the hugely popular film series. Bella and vampire Edward Cullen travel to Rio de Janeiro for their honeymoon after marrying, where they finally give in to their passions.

Kristen found filming the scene bizarre.

"There are two big sex scenes in the two [final] films, and we did them fairly early," she told the UK edition of Glamour magazine.

"It was so weird; it didn't even feel like we were doing a scene within a Twilight film. I was like, 'Bella! What are you doing? Wow! What is happening here?!' It was very surreal."

Off screen, Kristen and Robert Pattinson who plays mysterious Edward have enjoyed an on-off romance.

Kristen is keen to protect her personal life.

"It's funny when this question comes up, because I sort of feel like, I don't really care! People can say whatever they want." she insisted

"[The interest] is totally understandable, but when it's personal to you, it's like your life becomes a product and I'm repelled by that. I don't like to give away gems that people are gonna be like, Oh my God! So I'll always just shrug it off in fact, I always find it kind of funny, and not just with Rob."

Kristen has admitted to panicking about getting in shape ahead of shooting the movie, in which she has to wear a bikini. Her co-star Taylor Lautner is renowned for his fit physique, which Kristen envied when it came to working out.

"Usually we all make fun of Taylor [Lautner] for working out so often, and then suddenly me and Rob were like Sh*t' and were running around the block while Taylor laughed at us," she smiled. (C) Cover Media