The Backstreet Boys Honor Aaron Carter at London Concert: "We Lost One of Our Family Members"

"My heart is broken. Even though my brother and I have had a complicated relationship, my love for him has never ever faded," Nick wrote on Instagram alongside a collection of photos featuring him and his little brother. "I have always held on to the hope that he would somehow, someday want to walk a healthy path and eventually find the help that he so desperately needed. Sometimes we want to blame someone or something for a loss, but the truth is that addiction and mental illness is the real villain here. I will miss my brother more than anyone will ever know. I love you Chizz. Now you can finally have the peace you could never find here on earth….I love you baby brother."

"For Aaron– I'm deeply sorry that life was so hard for you and that you had to struggle in-front of the whole world," Duff wrote on Instagram. "You had a charm that was absolutely effervescent…boy did my teenage self love you deeply. Sending love to your family at this time. Rest easy."

Carter's twin sister, Angel, shared a selection of photos from their childhood with her followers on Instagram. "To my twin… I loved you beyond measure," she captioned her post. "You will be missed dearly. My funny, sweet Aaron,I have so many memories of you and I, and I promise to cherish them. I know you're at peace now. I will carry you with me until the day I die and get to see you again. 💔"

The band collectively tweeted, "We are saddened by the news of the sudden passing of Aaron Carter today. Our hearts go out to his family, friends and fans during this difficult time. Rest In Peace Aaron #gonetosoon."

"Sad to hear about the news of @aaroncarter😢," Hilton tweeted. "He was always kind to my family and I. He had a good heart. Gone way too soon. 😔Sending my thoughts and condolences to his loved ones and family. RIP 🙏."

"Sending love to the family and friends and fans of #AaronCarter. Rest In Peace!" Hart captioned a throwback photo of herself with Carter on Instagram.

Romano tweeted, "Incredibly sad about the passing of Aaron Carter. My thoughts and prayers go out to his friends and family. 🕯️"

"No…. This @aaroncarter news is heartbreaking…" Hilton tweeted. "This kid had such a spark. Known him for years and always really liked him, he was warm and really funny. Loved putting on a show and he was good at it. Ill find some pics of us and post more later… damn RIP budddd #aaroncarter."

"So very sad to hear about the untimely passing of #Aaroncarter. I did not know him well but in our short time together on RachaelVsGuy, I saw him as a sweet, good-hearted young man. My deepest condolences to his family, friends and fans. #RIPAaronCarter," Phillips tweeted.

"I worked with Aaron Carter on 7th Heaven," Knudsen tweeted. "Although he was young and famous, he took the work very seriously and was nice to everyone. Prayers up for his family and loved ones. Damn. #RIPAaronCarter."

"RIP sweet boy," Martyr tweeted. "You'll always hold a special place in my heart. I can't even believe this💔😭 You were one of the few people who never judged me & was always so supportive. My heart is broken hearing this news, I wish I had a chance to say goodbye. Rest In Peace Aaron."

"Met Aaron Carter in 2018, funny, talented and cool. I felt that he was trying....he really was just trying to be happy. I'm sorry to hear of his passing.. Condolences to his family and fans 💔," Love tweeted alongside a photo of Carter on "The Real."

Warren tweeted, "Fame at a young age is often more a curse than a blessing and Surviving it is not easy. RIP Aaron Carter🎤💔."

"Feel terrible about Aaron Carter passing away," "The Circle" star tweeted. "He always seemed like such a tortured soul. He just had his son. Now a boy is without a father and this man passed on far to young. Just a terrible tragedy of a day. RIP Aaron."

"Rest in peace Aaron Carter," Scarlette tweeted. "I am in tears right now hearing of your death. I just talked to you on Wednesday & you seemed in good spirits. You were such a sweet soul that never had a chance. I'm heartbroken that your son, who you wanted so much will never get to know you. 💔"