Do you really need to wear those Kristen? Slender Twilight star dons a pair of spanx for her public appearances in Los Angeles

She's the envy of many women due to dating Robert Pattinson but Kristen Stewart  still feels the need to wear spanx.
The 21-year-old actress appeared on The Tonight Show With Jay Leno in Los Angeles yesterday and was sporting the unattractive underwear.
Showing off her pale frame in a skimpy blue and black strapless dress, Stewart had thought carefully about her supportive knickers and ensure they matched her outfit.

Spanks on show: Kristen Stewart  accidentally showed off her underwear when she appeared on The Tonight Show With Jay Leno yesterday

Do you need those? The slender actress wore a tight-fitting black and blue strapless dress for her television appearance

As she sat on the famous sofa to talk about the latest Twilight film and her successful career, the star crossed her legs and as a result accidentally flashed her pair of spanx.
But that wasn't the only thing that the Twilight actress was showing off.
Whilst speaking about her upcoming film, Snow White And The Huntsman, in which Stewart plays the lead she told Leno about her unknown strength.
It seems that whilst she was filming a tense scene with her co-star, Chris Hemsworth, the actress accidentally punched him for real.

Magic underwear: The Twilight star had luckily matched her spanx to the colours of her dress

'When they call action, it doesn't matter how many times they've said watch this, be careful with this, don't hit him in the face,' she told the famous host.
The brunette admitted to Leno that when she was meant to miss the actor's face she actually hit him really hard.
'It made such a sound!' she laughed. 'It literally spun him right around, I knocked him right out of his close-up. It'll definitely be in the movie.'

Small but strong: The 21-year-old actress told Jay Leno how she accidentally punched her co-star whilst filming Snow White And The Huntsman

The U.S. star then turned to the audience and said: 'Girls, if you're wondering if it works - it does!'
Stewart also spoke of the upcoming fourth installment of the Twilight Saga, in which she finally becomes a vampire and also falls pregnant.
Speaking of her famous character, Bella Swan and her lover, Edward Cullen, she said: 'It's a trip to watch them be so happy.'

Wearing them all day: As Kristen lifted her leg up to mark her footprint onlookers caught a glimpse of her spanx underneath her dress

The awkward actress was pictured earlier in the day with her Breaking Dawn co-stars, Pattinson, and Taylor Lautner, at the Graumans Theatre.
The trio were there to take part in the hand and foot prints ceremony, which saw them get rather messy in public.
Wearing another skimpy dress, Stewart had also decided to wear her control pants for this appearance too and as she kneeled down with actors, her magic knickers were on show for everyone to see.

Messy stuff: The actress was with her Twilight co-stars Robert Pattinson and Taylor Lautner as they made hand prints at the Graumans Theatre in Los Angeles