Simon Cowell posted an emotional tribute to honor Liam Payne.
"You never really know how you feel about someone until a moment like this happens," Cowell explained. "Liam, I am truly devastated. Heartbroken. And I feel empty. 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."
Since Payne's passing, the record executive said he's been thinking about the "so many times" the two had together.
He also had a note for the singer.
"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," he explained.
Cowell was a judge on "The X Factor" when Payne was first a solo contestant as an early teen in 2008. He returned in 2010 when Cowell suggested he form a group with Harry Styles, Niall Horan, Louis Tomlinson and Zayn Malik.
The group placed third in the competition, but Cowell signed them to his label in 2011. The five ended up being one of the most successful boy bands of all time. Malik left the group in 2015, while the rest of the members continued to perform together. The rest of them decided to pursue solo careers in 2016.
"I had to tell you when you were 14 that this wasn't your time. And we both made a promise that we would meet again," Cowell remembered. "A lot of people would have given up. You didn't. You came back and within months the whole world knew 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."
The "American Idol" judge revealed that Payne had come to see him last year to just "sit and talk." He said that the two "reminisced about all of the fun times" they had together and how "proud" Payne was to be a dad to son Bear, with ex-partner Cheryle Cole.
"After you left, I was reminded that you were still the sweet, kind boy I met all of those years ago. I have met your son, Bear. He has your smile and that twinkle in his eyes you have.
And he will be so proud of everything you achieved. And how you achieved it," Cowell said.
The English television personality said that he's always thought of the five members of One Direction, or 1D, as "brothers" and believed it even more so after the members posted their heartfelt tributes to Payne this week.
"Now Liam, I can see the effect you had on so many people. Because you left us too soon.
Rest in peace, my friend," he said before sending his "love, thoughts and prayers" to the late singer's family.
Payne passed away on Wednesday following a deadly fall from a third-story hotel room in Buenos Aires, Argentina.
He was 31 years old.