She knows what to do! Jessica Alba dresses up charity T-shirt and checked shirt with red leather skirt for Stand Up For Cancer telecast

PUBLISHED: 15:46, 6 September 2014 | UPDATED: 19:22, 6 September 2014

She very rarely puts a foot wrong in the fashion stakes when walking the red carpet at various glamorous soirees.

But even when Jessica Alba is dressing down she pulls it off with exceptional style, which she proved when she arrived at the Stand Up For Cancer telecast on Friday.

The actress, 33, dressed up her black charity T-shirt with a chic leather skirt for the event at Hollywood's Dolby Theatre.

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Doing her bit: Jessica Alba kept things casual as she arrived at Hollywood's Dolby Theatre on Friday for the Stand Up To Cancer telecast

The Fantastic Four beauty kept her slim pins covered in a pair of black tights, after choosing the red flared number.

She kept her checked shirt tied around her waist, while boosting her frame with a pair of heeled biker-inspired boots.

Jessica completed her ensemble with soft waves in her hair, before taking to the stage to help raise money as part of the fourth biennial fundraising event.

She knows why she's there! The actress posed in a black T-shirt, complete with the organisation's logo

Always camera-ready! The 33-year-old kept her pins covered after opting for a flared, red leather skirt and tights

The mother-of-two was later seen chatting to fellow actress Sofia Vergara, who kept her curves covered in a similar top and cropped jeans.

The Modern Family star tweeted: 'On my way to Stand Up To Cancer! Tune in and help make a difference at 8pm/7CT. #SU2C'.

Before adding: 'Reunited with the most beautiful girl in the world!!!@reesewitherspoon', who was also involved in the telecast.

Support: The mother-of-two was spotted chatting to Sofia Vergara, who also sported a similar top and ripped jeans

Radiant: Jessica kept her low-key checked shirt tied around her waist, after styling her hair into soft waves

Despite her laid-back look, Jessica is serious when it comes to business - her Honest Company has been valued at a $1billion dollars.

Set up in 2012, the organisation creates chemical free baby items, including nappies and wipes.

After another round investment, the business has proved hugely successful, especially as Jessica only set it up because she struggled to find eco-friendly products following the birth of her daughters, Honor and Haven.