The Girls Aloud star became the celebrity ambassador of Nicola Dames's Vanilla Blush venture after her friend Connor Grant was left needing a colostomy bag following surgery in January, PA reports.
Coyle said: "I was amazed at the negative connotations that surrounds people with a stoma and also shocked at the lack of exposure in the mainstream media. This is one taboo which I am right on board in helping to smash.
"Nicola has turned people's lives around with her underwear. You can still look and feel gorgeous whilst having a colostomy or ileostomy."
Coyle confirmed on Twitter that she was donating one of her "favourite tops" to a charity backed by the company.
Dames added: "I am so excited to have Nadine on board. It's phenomenal to have such a celebrity figure supporting Vanilla Blush and raising awareness. With Nadine on board this is a real chance to smash the last remaining taboo."
