Cheryl Cole has shared the secret to her glowing complexion and healthy hair as she starred in a new vitamin advert.The 37 year old, who recently cut her workload to stop her feeling "nervous and stressed", took to her Instagram feed to post the clip in promotion of We Are Feel vitamins.The clip started with her applying a lipgloss while sitting in front of a vanity mirror in nothing but a white bath robe.The Girls Aloud star then smiled before applying mascara and taking a vitamin with water.