The reality star, who first competed on season 7 of the British competition show, died after a severe battle with an eating disorder.
"Nikki Grahame was a much loved housemate and a huge part of the Big Brother family. We are shocked and saddened by this awful news and our thoughts are with her family," the reality show’s Twitter account posted on Saturday. They also included a link to the charity Beat for those who are battling eating disorders.
Last month, her friends, Carly Cunningham and Leon Dee, created a GoFundMe while Grahame was getting "treatment in a specialist clinic" for her anorexia. "As some of you may know, Nikki is battling Anorexia. She has been battling for most of her life and as you can see, Nikki is now in a very bad way so we need to do something quickly," the post read.
On Saturday, the page was updated with the news of her death.
"It is with great sadness, we have to let you know that our dear friend Nikki passed away in the early hours of Friday 9th April," Dee wrote. "It breaks our hearts to know that someone who is so precious was taken from us at such a young age. Nikki not only touched the lives of millions of people, but also her friends and family who will miss her immensely."
Dee added that the funds raised would "be held safely in this GoFundMe until we have established an organisation supporting those suffering from anorexia to which we will make a donation in Nikki's memory. We will post updates for you with more details as soon as we have them."
"Rest In Peace, Nikki. We love you & not a day will go by without missing your smile. X X X," her friend concluded.
Grahame finished in fifth place on Big Brother UK in 2006 and appeared in her own reality series, Princess Nikki. She was the runner-up on Ultimate Big Brother in 2010, and competed as a guest housemate in season 16 of Big Brother UK. Additionally, she also competed on the fourth season of Big Brother Canada, where she finished in sixth place.
Over the years, Grahame was vocal about her anorexia, writing two books about her struggles; Dying to Be Thin (2009) and Fragile (2012).
Following the news of her death, friends, former colleagues and fans took to social media to express their condolences.
Jameela Jamil, who's previously opened up about her own personal struggles with an eating disorder, wrote, "Horrifying to hear about Nikki Grahame. What a tragedy. Eating disorders are the highest cause of death in any mental illness," before calling out a website and their ads about weight loss.
Horrifying to hear about Nikki Grahame. What a tragedy. Eating disorders are the highest cause of death in any mental illness. Would be great if articles like this one could stop posting a diet tool under an article about an eating disorder related death @SkyNews Have some sense. pic.twitter.com/ncpEeNWlBx
Big Brother Canada host Arisa Cox wrote how "heartbroken" she was over Grahame's death.
"HEARTBROKEN to hear this devastating news that the incredible force of nature that is Nikki Grahame has passed away," she tweeted. "We messaged some love to each other just a few weeks ago and I cannot believe this is happening. We love you Nikki."
HEARTBROKEN to hear this devastating news that the incredible force of nature that is Nikki Grahame has passed away. We messaged some love to each other just a few weeks ago and I cannot believe this is happening. We love you Nikki 💔💔💔 pic.twitter.com/GGY286uBz4
Having been so public with her anorexia battle, I can only imagine how many important conversations were started because of Nikki, and how many people she has inadvertently helped over the years without even knowing. RIP 💔