'Sexy goddess' Kristen Stewart

Robert Pattinson thinks Kristen Stewart is a "sexy goddess".

The 25-year-old actor - who is dating his 'Twilight Saga' co-star off-screen - admitted Kristen looked "amazing" when her alter-ego Bella Swann turned into a blood-sucking "vampire queen" during the latest film in the franchise.

He said: "She was a sexy goddess. She looked amazing. It was funny because Bella is that girl that is always tripping on things, and then, she turns into this elegant woman, like a vampire queen.

"Kristen had the best twist in the plot!"

However, Robert - who plays vampire Edward Cullen in 'Twilight' - admitted the couple's on-screen sex scene was far from easy because there were so many crew members who wanted to have a say in how the pair's intimacy panned out.

He added in an interview with Brazil's Capricho magazine: "I was trying to do a sex scene and there was huge guy lying on the floor, looking at me and telling me what to do.

"The hardest thing was that, in normal movies, when you're doing a sex scene, people don't pressure you a lot because the director doesn't want to intervene and suggest how he would do that.

"But in 'Breaking Dawn', it was different, there was too much expectation. How to make all the people that were waiting for that moment happy."