(Cover) - EN Showbiz - Kristen Stewart did not want her Twilight character's proposal scene to "look stupid".

The 21-year-old actress plays Bella Swan in the popular vampire franchise.

Bella and Edward Cullen - played by Robert Pattinson - got engaged onscreen in 2010's third installment The Twilight Saga: Eclipse.

Kristen wanted the controversial scene to appear natural.

"Well, to decide you're gonna marry someone at 18 is a pretty hefty decision. And I didn't want to look stupid," Kristen told MTV News.

Kristen was most concerned with how she portrayed the momentous decision from a teenager's perspective.

The star did not want Bella and Edward's engagement to be viewed as frivolous.

"I didn't want it to look like kids getting married. You know what I mean? I wanted to be, like, 'Oh! Wow! I would say yes too,'" she explained.

Kristen put a lot of effort into the newest film in the series, The Twilight Saga: Breaking Dawn Part 1.

Shooting the mature sex scenes was a unique experience for the star.

"There are two big sex scenes in the two [final] films, and we did them fairly early," she recently 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."

The Twilight Saga: Breaking Dawn Part 1 will be in US theatres on November 18. (C) Cover Media