Usain Bolt has revealed that he is set to return to Borussia Dortmund for three weeks as he continues his bid to become a professional footballer.
The Jamaican sprint legend had a two-day stint with the Bundesliga giants last month, although head coach Peter Stoger suggested he was not yet ready for the top level.
But Bolt insists a football career is no joke to him and he is determined to improve, with a second spell at Dortmund helping him to assess his progress.
"It's a big deal - everyone feels like I'm just kidding around, just joking, but I'm serious," Bolt told the Herald Sun, speaking at the Commonwealth Games in Australia.
"I'm actually going back to Dortmund in a couple of weeks, to work with them for three more weeks. I need to assess myself at a better level to see what level I'm at, what I need to do and if I can. That's something I'm focused on.
"I'm looking forward to the challenge, because that's what I want - I want a new challenge in life."
Asked whether he can make the necessary adaptations to succeed in football, the eight-time Olympic champion replied: "It's a little bit more technical, but I've shown in my life that I've always adapted myself.
"With soccer, I played in high school a little bit - even while I was running, I played with my friends. The first trial I went to, they were very impressed. They didn't expect me to know so much, to understand the game.
"It's all about improving right now. I personally think I can do it. I'm a hard worker and I'm determined."
And Bolt says this is his sole focus now, ruling out any return to the track for the 2020 Olympic Games in Tokyo.
"For me, I have already accomplished what I can when it comes to track and field," he said.
"I'm trying to move on to another goal, to soccer. I'm trying to do something else."