Louis Tomlinson has Calvin Harris to thank for his collaboration with Steve Aoki.

The former One Direction star was meant to see the 'This Is What You Came For' hitmaker perform in Las Vegas but when he couldn't make it, Steve replaced him and it was after seeing him there that Louis decided to get in touch.

He shared: ''I was on holiday with my friends in Vegas, and we were meant to see Calvin Harris' show ... [My friends and I] had an incredible night at [Steve's show]. It was really, really fun. The show was amazing.''

The pair collaborated on Louis' debut single 'Just Hold On', which they performed for the first time in December as a tribute to Louis' late mother Johannah Deakin, who passed away only a few days prior to their performance after an aggressive battle with leukaemia.

Of the track, Steve told Rolling Stone magazine: ''I didn't want to make an EDM record with an EDM arrangement ... It was really about the lyrics, how to make the lyrics stand out musically on my part.

''When we started out, it was really more of sad, slow song. We needed it more uplifting. We needed to speed it up. We needed more energy to the song ... It's the most human song I've produced.''

Meanwhile, Louis previously admitted his first performance of the track felt like a ''little send off'' to his mother.

He said: ''It's not something that I feel 100 per cent comfortable talking too much about but just quickly, when I first found out the news I kind of did want to throw the towel in. But it was my mum who said to me that I've just got to keep going, telling me very sternly that she wanted me to. So I'm not doing it for her but ... It was tough but I felt like it was nice for me to almost have a little send off for her.''