TV presenters Rylan Clark and Vernon Kay led the tributes for S Club 7 star Paul Cattermole after his death.
Paul, 46, was found dead at his home in Dorset and there are thought to be "no suspicious circumstances" around his death.
His death comes only weeks after the band shared their plans for a reunion tour.
After hearing the tragic news, Rylan, Vernon, and Lizzie Cundy were some of the stars who took to social media to pay tribute to him.
"Sending all the love to you all xxx," Strictly Come Dancing : It Takes Two presenter Rylan wrote.
S Club 7 ‘to announce reunion’ 25 years after 90s pop group’s first singleVernon also paid tribute to Paul and said the singer “always had time for a chat”.
“This is so very sad,” Vernon. tweeted.
“From when I first started in TV all the way through CBBC, T4, TOTP, smash hits poll winners Paul and Sclub were always there. He always had time for a chat. RIP.”
Socialite Lizzie Cundy said: "So shocked and sad to hear S Club 7 Paul Cattermole has past away.
"Such a lovely guy . All my thoughts and prayers are with his family and friends #RestInPeace."
Lorraine Kelly wrote: "This is so sad. Lovely man and he was so looking forward to the #sclub7 reunion. Interviewed them all many times and struck by how gentle and shy he was."
Nicki Chapman posted: "Just heard the terribly sad news about Paul from @SClub7.
"I have such fond memories of working with him over the years. My thoughts go to his family and the band."
Broadcaster India Willoughby posted: "Omg. Such sad news. Paul was always my favourite. Cheeky smile. Be with the brightest stars now. Love and condolences to all his family and friends."
Shayne Ward said it was a “privilege” watching Cattermole perform.
S Club 7 star Jo O'Meara spotted on stroll after four agonising back surgeriesThe singer who won the second series of The X Factor tweeted: “#rip #paulcattermole @Paulcattermole1 Was a privilege watching you do what you do best when I was growing up. Was and still am a big of fan of you and the gang. My condolences to paul’s family and extended family @SClub7 x." [sic]
Meanwhile, Irish singing duo Jedward shared their shock at the “devastating” news of Paul's passing.
On the S club 7’s Instagram post, announcing Cattermole’s death, Jedward commented: “This is devastating sending you all Love Surrounding you with strength!”
Paul's bandmate Hannah Spearritt is said to have "broke down" when she was given the heartbreaking news and his bandmates have been left in "horror and disbelief".
A statement released by the band said: "We are truly devastated by the passing of our brother Paul. There are no words to describe the deep sadness and loss we all feel.
"We were so lucky to have had him in our lives and are thankful for the amazing memories we have.
"He will be so deeply missed by each and every one of us. We ask that you respect the privacy of his family and of the band at this time."