The BBC Radio 1Xtra presenter, 27, tragically lost both her mum and sister to breast cancer, and then found out that she is a carrier of the BRCA 1 gene.
Carrying the gene gives Claira an 85 per cent chance of getting the disease so she has decided to have her breasts removed this month.
Claira will document her journey with a special documentary, which will be shown in March. She has also written a blog, explaining her decision.
She said: "I've chosen to share my story and my journey with as many people as I possibly can and the beginning seems like a good place to start.
"When I was nine years old my mummy died of breast cancer leaving a big hole in mine and my families lives. I know her death changed the course of our lives forever."
Claira revealed her sister later found out she had cancer at 25, and died six-and-a-half years later. That's when Claira decided to be tested for the BRCA 1 gene.
She continued: "I found out a double mastectomy was pretty much the only preventative measure. Armed with this information I went and got on with my life.
"I always said to myself I would be in a steady, stable and loving relationship when I did this. That way no matter how I looked afterwards that person would still love me.
"But instead I'm single. I don't have kids, in fact, I won't have kids until this has been done.
"My worst fear is having children and having to leave them."
While she admits that sometimes she worries about how she will look after the operation, Claira says it isn't really a big deal.
She said: "One thing I have learnt is that we get this life once. I've spent a lot of it feeling sad and unhappy.
@My sister's death was a turning point. She doesn't have her life but I have mine. I have and will continue to strive to make my life one of happiness, positivity and purpose."