As one of Hollywood's hottest young actresses, Megan Fox is usually seen looking immaculate on the red carpet in a designer dress and perfect make-up.

But after being spotted looking au naturel on Monday, the 23-year-old dashed into a cosmetics store for a make-up fix.

Fortunately for the Transformers beauty, she still looked just as attractive, albeit a bit tired and washed-out.

Dressed down in black jeans, a grey T-shirt and Ugg boots, Fox didn't look ready to be photographed as she was caught shopping in the Los Angeles suburb of Studio City.

After spending some time talking to an assistant in the Planet Beauty store, Fox then splashed out a few hundred dollars and left with a bag laden with dozens of items. The actress likes to spend a lot on her appearance and is said to pay $300 a time for a beautician to give her a facial at home every week.

After a few months out of the limelight, Fox has a busy summer coming up promoting her new films Jonah Hex and Passion Play. Her Passion Play co-star Mickey Rourke has publicly praised the actress and insists critics will be surprised by her performance in the upcoming drama.

Meanwhile, Fox recently teamed up with her long-time boyfriend Brian Austin Green to attack California Governor Arnold Schwarzenegger's funding cuts to the state schools. Appearing in a campaign video, Fox urges Californians to 'call, write and annoy the governor until he cries for his mommy'. In the three and a half minute video, she says more than $17billion has been cut from state educational programmes over the past two years. Fox has been a surrogate stepmother to Green's son Kassius, eight, since the pair started dating six years ago.