Simon Cowell feels "lucky" to have met One Direction.

Simon Cowell

Simon Cowell

The music mogul put together the boy band - which comprises of Harry Styles, Liam Payne, Niall Horan, Zayn Malik and Louis Tomlinson - 10 years ago after they appeared on 'X Factor' as solo artists, and to mark their tenth anniversary, he remembered the "special" day.

Alongside a picture of himself with the band, celebrating getting through the next round of the show, he wrote: "Today is a very special day. I was lucky enough to meet five guys. Who were so much fun. So talented. It feels like 10 minutes ago. And you made it happen."

Elsewhere, Harry Styles paid tribute to his One Direction bandmates on their 10th anniversary, where he revealed how proud he was of them and all they had achieved together.

Harry tweeted: "I've been struggling to put into words how grateful I am for everything that's happened over the last ten years. I've seen things and places that I'd only ever dreamt of when I was growing up.

"I've had the pleasure of meeting and working with some of the most incredible people, and gained friendships that I know I will treasure for the rest of my life. None of this would be possible without the support you've given along the way. And for that, I will be forever thankful. I just can't believe it's been ten years. Thank you to our crew, our team, and everyone else who helped us along the way. To all the fans, I love you, and I thank you with all my heart. You did it all, and you changed everything. And finally.. to the boys, I love you so much, and I couldn't be prouder of everything we achieved together. Here's to ten. H (sic)."

Louis, Niall and Liam all shared their own messages about the anniversary on social media.