By ANDREA MAGRATH
Gleeful girlfriends:Glee star Dianna Agron and her I Am Number Four co-star Teresa Palmer get cosy at the film's premiere in Los Angeles
She plays good girl cheerleader Quinn Fabray in the hit show Glee, and Dianna Agron stayed true to form for the premiere of I Am Number Four, her first starring role, last night.
But while the 24-year-old was lovely and ladylike in a cream cocktail dress, her co-star Teresa Palmer was the polar opposite, stopping traffic in a thigh-baring gown by Emilio Pucci.
Angel-faced Dianna looked effortlessly elegant in her chiffon dress by Vivienne Westwood for the screening at the Village Theatre in Los Angeles.
The 24-year-old wore her hair in a flirty bouffant ponytail and added a splash of colour with ruby satin Brian Atwood pumps.
Dianna walked the red carpet with the film's star, and her boyfriend, Alex Pettyfer.
The couple, who got together while filming the sci-fi thriller last year, recently denied rumours of an engagement after Miss Agron arrived at a press conference for the film wearing a diamond band on her wedding finger.
Leggy: Australian actress Teresa Palmer, Russell Brand's ex, stopped traffic in a thigh-baring, backless gown by Emilio Pucci
But while Dianna and Alex certainly make a beautiful couple, all eyes on the red carpet were undeniably on their co-star, Australian actress Teresa Palmer.
The Sorcerer's Apprentice actress, who used to date Russell Brand, smouldered in a sheer, backless gown by Emilio Pucci.
The sequinned dress featured a thigh-split that showcased the 24-year-old's toned limbs.
Ladylike: Dianna wore a demure cream dress by Vivienne Westwood for the premiere of her first starring role
Teresa has been named as the breakout star of the film for her high-energy action scenes as mythical teen with super powers, 'Number Six.'
But Teresa revealed that some of her harder stunts were performed by a body double - who was a man.
She told celebrity blog Just Jared: 'His name is JaJa. He’s this incredible athlete from China and he’s sort of my height.
Taking it slowly: British actor Alex Pettyfer and Dianna, who met while filming, have recently denied engagement rumours
'He’s a lot more muscular than myself. He doesn’t really have long curly blonde locks. It’s a wig.'
I Am Number Four, based on the best-selling novel, follows John (played by Pettyfer), a superhuman teen of the mythical Lorien race.
He masquerades as normal high school student to hide from a deadly enemy seeking to destroy him, after killing three others of his kind.
Girl power: Kick-Ass actress Chloe Moretz and Amanda Michalka both attended the screening
Big boss: Steven Spielberg, whose studio produced the thriller, turned up to show support
Dianna plays charming and popular girl Sarah, who falls for her new mysterious new classmate after breaking up with the school jock.
The film is already receiving rave reviews, with one critic calling it an 'edge-of-your seat thrill ride.'
Steven Spielberg, whose studio Dreamworks produced the thriller, turned out to support the film, but unlike the well-dressed stars, he wore a weathered leather jacket and baseball cap.
Kick-Ass star Chloe Moretz also attended, and according to onlookers, struck up a friendship with Miss Agron at the after-party.
Some of Dianna's Glee co-stars, Harry Shum and Chord Overstreet, rushed to get to the screening in time after filming.
Harry Shum tweeted last night: 'Just got off work and rushing to I AM #4 premiere with @chordoverstreet to support @alittlelamb (Agron's Twitter name). Part the traffic!!'
Dianna also took to Twitter to thanks her fans: 'So much fun tonight at the premiere. The love and support was amazing!'
The actress, from Savannah, Georgia, has managed to avoid answering questions about her relationship with the film's star during press for the movie.
Action star: Teresa is winning acclaim for her high-energy stunts and action scenes in the film
On-set romance: Dianna and Alex sparked up a relationship while filming the sci-fi thriller
She would only say that Alex was 'great' to work with 'because he was so enthusiastic and so determined to give everything he had to this character.
'He wasn't a diva, so that was good,' she added.
Pettyfer, who previously starred in Wild Child with Emma Roberts and Beastly with Vanessa Hudgens and Mary-Kate Olsen, was equally coy, only saying that Dianna is 'a lovely girl. I was very fortunate to work with her, and she was amazing in I Am Number Four.'
I am Number Four - Official Trailer [HD]
source: dailymail [endtext]