Simon Cowell has paid tribute to One Direction star Liam Payne, saying he is "heartbroken" and feels "empty" following the singer's death.
Cowell, who put the group together on The X Factor in 2010, remembered Payne as "kind, funny, sweet, thoughtful [and] talented".
"Liam, I am devastated. Heartbroken. And I feel empty," he wrote.
Payne, 31, died on Wednesday when he fell from the balcony of the third-floor hotel room where he had been staying in Buenos Aires, Argentina.
In a post on Instagram, Cowell added: "And I want you to know how much love and respect I have for you. Every tear I have shed is a memory of you."
The talent show judge also said he had been thinking about the time they had spent together.
"I wanted to let you know what I would always say to the thousands of people who would always ask me. What is Liam like?
"And I would tell them you were kind, funny, sweet, thoughtful, talented, humble, focused. And how much you loved music. And how much love you genuinely had for the fans."
Payne's girlfriend Kate Cassidy has also paid tribute to the star who she called "my angel", adding she was "at a complete loss".
"You are everything," she said in a statement.
"I want you to know I loved you unconditionally and completely. I will continue to love you for the rest of my life."
It come as Payne’s father, Geoff Payne, arrived at the morgue in Buenos Aires where his son's body was taken on Friday afternoon.
Argentine authorities have said a family member needs to identify Payne's body before it can be released and repatriated to the UK.
In Cowell's statement, he also recalled Payne’s first X Factor audition in 2008, at the age of 14, when Cowell told the budding singer he was not ready and to come back in two years.
"A lot of people would have given up. You didn't. You came back and within months the whole world would know Liam.
"And you never forgot the fans. I watched you spending so much time with people who had wanted to meet you. You really cared."
Cowell eventually signed One Direction to his label and masterminded their global success before they split in 2016.
The music mogul also revealed that Payne had visited him last year.
"Not for a meeting. Just to sit and talk. And we reminisced about all of the fun times we had together. And how proud you were to be a Dad," he wrote.
"After you left, I was reminded that you were still the sweet, kind boy I had met all of those years ago."
He added: "I have met your son, Bear. He has your smile and that twinkle in his eye that you have. And he will be so proud of everything that you have achieved. And how you achieved it."
Cowell's tribute came after Payne's former bandmates posted their own heartfelt memories.
"I always thought the five of you in the band as brothers," Cowell continued. "And regarding their messages today I believe you were.
"And now Liam, I can see the effect you had on so many people. Because you left us too soon."
Also on Friday, Payne's bandmate Niall Horan posted a tribute, saying he was "absolutely devastated" by the "passing of his amazing friend".
Harry Styles earlier said his "heart breaks" for Payne's family. He added: "His greatest joy was making other people happy, and it was an honour to be alongside him as he did it."
Louis Tomlinson echoed Styles' sentiments, describing Liam as "the most vital part of One Direction" who had a "gift for writing".
Zayn Malik spoke to Payne directly in his statement, praising him for his "positive outlook and reassuring smile".
Others posting their reactions included another former X Factor judge, Sharon Osbourne, whose message to Payne said the music business "let you down".
"Where was this industry when you needed them?" she wrote.
"You were just a kid when you entered one of the toughest industries in the world. Who was in your corner? Rest in peace my friend."