Louis Tomlinson and Steve Aoki's 'Just Hold On' has topped the iTunes charts.

Louis Tomlinson and Steve Aoki

Louis Tomlinson and Steve Aoki

After the pair debuted their collaboration on 'The X Factor' on Saturday (10.12.16), in a tribute to Louis' mother Johannah Deakin who died during the week following a secret battle with leukaemia, fans rushed to buy the track and it shot to the top of the iTunes charts in the UK and in many countries around the world.

Steve shared a picture of the UK iTunes charts on his Snapchat account and wrote: "Wow thank u. Number 1!!! (sic)." He also included an emoji of the British flag.

The track pushed Louis' former bandmate Zayn Malik's collaboration with Taylor Swift, 'I Don't Wanna Live Forever', into the number two spot.

Speaking after the performance on 'The X Factor', Simon Cowell told a tearful Louis: "I have to say something to you. I've known you for six years, what you've just done - the bravery.

"I respect you as an artist and I respect you as a person. Your mum was so proud of you Louis and she was so looking forward to this performance. She's watching over you now and you've done her so proud."

The 24-year-old singer bravely took to the stage to perform the track in memory of his mother, as she had been eagerly looking forward to his planned performance.

It features the poignant lyrics: "What do you do when a chapter ends / Do you close the book and never read it again / Where do you go when your story's done / You can be who you were or who you'll become."

The upbeat song - which ended with the four judges, Simon, Sharon Osbourne, Louis Walsh and Nicole Scherzinger, and the 12,000 strong crowd at Wembley Arena giving Louis an extended standing ovation - also features the lyrics: "If it all goes wrong, darling just hold on / The sun goes down and it comes back up / The world, it turns no matter what / If it all goes wrong, darling just hold on."