They found fame together on the 2006 series of Big Brother.
And Imogen Thomas has detailed her struggle to save Nikki Grahame from her battle with anorexia in a moving tribute following her tragic death.
'There was nothing more we could do to save Nikki... I'm broken,' the reality star, who appeared alongside Nikki in Big Brother in 2006, emotionally told her followers on Instagram in a lengthy post on Sunday.
Besties: Imogen Thomas detailed her struggle to save Nikki Grahame from anorexia after her tragic death on Friday (pictured together on Big Brother in 2006)
She wrote: 'I have no words. I miss talking to you everyday. I miss your funny personality. I miss you impressions. I miss your tantrums. I MISS YOU. I'm utterly broken.
'My best friend...You were special and so beautiful. You were kind and funny. It went too far and I'm so sorry I couldn't save you. We all tried so hard. Now you're gone too early. You had so much more to give.
'You were unbelievably strong. I take comfort in all those memories we made, those epic holidays, those crazy all dayers, just sitting at home listening to Old Skool music. I will cherish them forever.
'My girls and I will love you and remember you always until we meet again. I'm sorry my angel.'
'I miss talking to you everyday': Imogen took to Instagram to post a touching tribute to her late friend
Imogen continued: 'Thank you for all your messages. I need time to grieve over my best friend.
'We tried everything to beat that soul destroying illness. I'm broken. Please hold the ones you love close and tell them you love them. Life is too short.
'There was nothing more we could do to save Nikki. I will take some time out of social media. Thank you again for your messages... Nik would be so touched.
'I'm sorry Nik. I love you.'
'You had so much more to give' The reality star mourned the loss of her best friend as she told her followers she would be taking time out from social media to grieve
Imogen was among the group of supportive friends who raised £65.5k to pay for Nikki to attend a specialist clinic for her illness.
The reality star had checked in to a private hospital last month for professional care.
It is believed that the star, who rose to fame after appearing on the 2006 series of the hit reality show, was released from hospital in Devon a day before her death.
'Life is too short' Imogen told her followers to hold the people they loved close in the touching tribute
Nikki's death was confirmed online by her friend Leon Dee on Saturday.
A statement on the GoFundMe page read: '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.
'It breaks our hearts to know that someone who is so precious was taken from us at such a young age.
'I'm sorry Nik. I love you': Imogen apologised to her late best friend as she called her 'beautiful' and 'funny' in the post
The statement continued: 'Nikki not only touched the lives of millions of people, but also her friends and family who will miss her immensely.
'We would like to request privacy at this difficult time, while Nikki's friends and family process the sad news. Full details will be released as and when we know them.
'All donations have been greatly appreciated and it was heartwarming for everyone including Nikki to see how much she was loved.'
Medical treatment: The reality star had checked in to a private hospital last month for professional care
Leon added that all the funds raised in the GoFundMe will be given to a charity as a donation in Nikki's memory.
He penned: 'Funds will 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. We are working with GoFundMe at this time. If you want to request a refund, you can write into GoFundMe's team here.
'Rest In Peace, Nikki. We love you & not a day will go by without missing your smile.'
Tragic: It is believed that the star was released from hospital in Devon a day before her death
While a statement from her representative said: 'It is with immeasurable sadness that Nikki Grahame passed away in the early hours of Friday 9th April 2021. Please respect the privacy of Nikki's friends and family at this tragic and difficult time.'
Nikki appeared on the seventh series of Big Brother UK in 2006, finishing in fifth place. She returned to the show in 2010 for the Ultimate Big Brother series.
After entering the house dressed as a Playboy bunny, Nikki quickly became known for her temper tantrums and Diary Room histrionics, including the now infamous 'who is she?' rant.
Nikki was evicted on day 58, but went back into the house after the remaining contestants picked her to return.
After Big Brother, she bagged her own reality show, Princess Nikki, which saw her attempt to keep various jobs.
She also appeared on a slew of shows including Celebrity Scissorhands, 8 Out Of 10 Cats and The Weakest Link, and a Channel 4 poll named her the 12th most 'written about' person of 2006 in the UK.
Friendship: Nikki appeared on the seventh series of Big Brother UK in 2006 with Imogen and finished in fifth place (pictured together in London)