Cheng, 25, who loves singing karaoke, was encouraged by his friends to enter TVB's competition, The Voice.
He had already decided to try to improve his singing by enrolling in voice classes. His progress led to his friends suggesting he should audition for the show. His experiences, as he progressed week by week singing in front of a studio audience, gave him greater confidence as a performer.
The former student of Methodist College, in Yau Ma Tei, used this added poise and assurance at the Wushu World Championships, in Ankara, Turkey, two months ago, when he and his Hong Kong teammates won gold in the men's taolu duilian event. This involves two or more people competing together while performing martial arts manoeuvres, such as stances, kicks and punches.
"With my friends' support, I'd had enough courage to enter the talent contest," Cheng says. "I'd been very curious to know if my singing was improving after taking classes for several months. I thought the talent show could be a good test for me and the judges' comments helped me to measure my progress.
"The judges in the singing contest were really helpful. Their comments taught me how to perform well on a stage - not only when singing, but also in a sports event like wushu."
Cheng had never expected to progress very far in the show. But his singing skills took him past the preliminary selection rounds and onto the show itself, where he sang in front of a television studio audience.
To his surprise, he survived the show's early elimination rounds - which proved a problem, as the wushu world championships got nearer. He suddenly found he was having to spend more and more time training with Hong Kong's wushu squad in Beijing - and less time on the television show.
"I had to travel to and from Beijing and Hong Kong because I needed to record the show," he says. "I had to make three or four trips between the two cities during that time."
His problems increased as his singing success helped him reach the last 10 contestants - just as his place in Hong Kong's team for the world championships was confirmed. "That proved impossible for me; the two competitions totally overlapped," he says. "I couldn't find a solution, despite my best efforts.
"Before I applied to take part in the television talent show, I'd got the consent of my wushu coaches and the Hong Kong Wushu Union. I had the full support of everyone in the Hong Kong team, but I didn't think I could stay on the show when the world championships were around the corner.
"The three of us in the team were hoping to win a medal in the duilian [dual] event; it wasn't fair on the others if I wasn't totally focused on that."
So Cheng quit the show - recording an announcement that was broadcast during the programme.
"If I'd the chance, I would have stayed on the show until I was eliminated," says Cheng, who took part in the 2008 Beijing Olympics exhibition event and last year's Asian Games. "Sadly that didn't happen. I ran out of time."
After winning the team gold at the world championships, he returned to Hong Kong, and staged a mini-concert at a celebration for their medal success.
He was able to share his talent for singing with his friends, once again, even if he was no longer trying to win a talent show. "One day I will have to retire from wushu," he says. "It's too early to say if I can earn a living from singing. But my singing experiences have been positive.
"I've learned we should always make plans to try to achieve our dreams. Our plans may change, but our dreams will never have the chance to come true if we haven't made a plan first."