Kristen Stewart says Taylor Lautner has "many more layers to him" than meets the eye.

The American actress stars alongside Taylor in the hugely popular Twilight Saga, which also features Robert Pattinson. Kristen has become close to both her on-screen lovers since joining the film franchise in 2008.

The stunning star who has enjoyed an on-off romance with Robert in real life says Taylor surprises most people behind the scenes.

"I don't know if there's much that would surprise people about Rob, except that he's probably more fun-loving in private than may come across in public," she told the Chicago Sun Times.

"As for Taylor, I think people might be surprised to learn there are so many more layers to him. Yes, he's a lot of fun and all that, but he's a lot deeper than I think comes across in the media."

The Twilight Saga: Breaking Dawn Part 1 is the first instalment of the two-part finale of the film series.

The new movie sees Kristen's character Bella Swan marrying her vampire sweetheart Edward Cullen, played by Robert.

Kristen was thrilled with the joyous storyline.

"The biggest change for me in this film was that Bella finally gets to be happy at least for a bit of time. While clearly she exhibits a lot of bridal jitters tied to the wedding scenes at the beginning of Part 1, there's some genuine joy there for both her and Edward," she explained.

"Bella showcases so many different sides to her personality and her reality. There's Bella the new bride, then there's the pregnant Bella, the human Bella, the vampire Bella, it's really a wild ride. But as an actress, it was all so rewarding."

Both instalments of Breaking Dawn were filmed at the same time. Kristen says such shooting methods required maximum concentration.

"We really had to keep focused over the six months we worked on this. In the morning we might film an intense scene from Part 2, but then in the afternoon would be something more fun but from Part 1," she said.

"We really had to pay attention!"