The Xtra Factor host showed off her signature dip dye hairstyle in promo shots for the hair and beauty brand.
Flack said of her new role as brand ambassador: "It was so exciting to be asked to be the new face of Regis Salons. I jumped at the chance!
"I've always loved to experiment with my hair and regularly visit the salon to make subtle changes to the length or colour to keep the style looking fresh.
"What I love about Regis is that, as well as being experts in recreating the latest looks from the catwalks and the red carpet, they really care about great hair.
"It's good fun to try out new styles and colours but as long as your hair is looking healthy you'll always feel more confident.
"If I have a bad hair day I feel more self-conscious and it can affect my mood, so it's really important for me to take care of my hair."
Flack recently hosted an evening of live music in London to celebrate Arthur's Day - the anniversary of Arthur Guinness signing a 9,000-year lease on the famous brewery.
She "marries" Louis Walsh in Las Vegas on this weekend's Xtra Factor.
Watch Caroline Flack behind the scenes of her Regis photoshoot below: