After One Direction announced their indefinite hiatus in 2015 to focus on solo careers, Louis Tomlinson spent most of his time on being a father to his son Freddy Reign, who he welcomed nearly a year ago and will celebrate his first birthday on Sunday (January 21).

Last month, Tomlinson faced a huge hardship when he lost his mother to leukemia at the age of 43, which almost made him quit his solo endeavors altogether. But despite the hurdle, he performed his debut solo single "Just Hold On" featuring Steve Aoki on The X Factor U.K. a few days after the tragic news in honor of his late mother. The song was originally written as a fight song for everyday life struggles, but the timing of his mom's death made the song a personal tribute piece.

"When we wrote the song, it was more about any kind of hardship in life you might have to struggle with," Tomlinson, who was joined by Aoki, told On Air with Ryan Seacrest in-studio on Friday. "That wasn't the intention deliberately. It's kind of saying don't feel sorry for yourself; keep fighting, keep strong. So those two kind of fell into place and that obviously made the performance more personal for me."

Tomlinson admitted the song was "hard to sing," but it was his mom who pushed him to perform before she passed away: "I was motivated by my mom and I had a conversation with her, and I said I wasn't sure I would be able to do it. She said I had to do it." 

"Just Hold On," came into fruition when Tomlinson and his friends were in Vegas to see Calvin Harris perform, but he was unable to perform so Steve Aoki was called to fill in. "We just had the most incredible night. It was so fun," Tomlinson said. "So after that, I just messaged Steve on Twitter, kind of maybe a little audaciously said: 'Can we work together? Your show was amazing.'"

Aoki added: "Twitter works! It's crazy. You think it's one of those long-gone social media platforms, but that's the best way to communicate from artist to artist."

Tomlinson also revealed he wasn't sure about pursuing a solo career in the first place, but he knew he was going to continue writing music. When they wrote "Just Hold On," which is one of the first songs he penned, he decided to record the track and have Aoki produce it with Top 40 synthetic beats.

"I was just looking at radio and there's a lot of this style of music on radio at the moment. I know it's kind of different enough with what we were making with One Direction, so it seemed like a smart route for me," Tomlinson said.

Although the members of One Direction are focusing on their individual careers -- Niall Horan dropped his debut solo single "This Town," Harry Styles worked on the Christopher Nolan war drama Dunkirk,  and Liam Payne signed with Republic Records -- Tomlinson said that they are still in connect and are very supportive of each other's solo endeavors.

"We worked so relentlessly for five years, we all needed a bit of space and a bit of time for ourselves to do things that maybe we couldn't have done inside the band," Tomlinson said. "We're all super supportive and all the boys came to The X Factor performance, which was really, really nice...There absolutely isn't [tension]. It's really nice that the boys can be there to support me and also celebrate."

You can purchase "Just Hold On" on iTunes here.