The 33-year-old 'Piranha' star stepped out of her London house to attend the taping of a TV show wearing a glamorous bright blue frock, reported Daily Mirror.
She smiled for the waiting photographers, but Brook failed to realise her zipper wasn't done up and left her dress gaping at the back.
Meanwhile Brook said she and former boyfriend Danny Cipriani are just friends insisting she is actually 'single'.
Even though she flew off to Paris with him at the weekend and she wrote on Instagram, "Love you so much Danny Cappucino.