Olympian silver medalist Louis Smith twice left gymnastics.
A 29-year-old man represented the UK at three Olympics, and from 2008 to 2016 he also won two bronze medals.
He won three silver medals at the World Championships, two European gold and the Commonwealth Games title in 2006.
"I had to make a difficult decision to hang my shirt," said Smith, who was named MBE for Gymnastics in December 2012.
Smith, who was diagnosed with ADHD at the age of seven, says he intended to return to gymnastic training for the Tokyo 2020 Olympics, but changed his mind as a result of changes in qualifying criteria and new "exciting opportunities".
"Gym gave me everything," said Smith, who announced he had retired at the ITV show Lorraine. "I was given the tools I needed to direct my ADHD throughout my childhood, and when I grew up in this sport, I quickly found some intention in my life, and that's from my man today.
"Since my young age, it has become my dream to compete in the Olympics and to represent the UK to have the opportunity to do it on three different occasions and bring home four Olympic medals in this process, it's something I will forever love and for which I am eternally grateful . "
His bronze medal in 2008 in Beijing. they saw him having been the first Olympic medalist in Britain since 1928, and since 1908 he has been the first British man to receive an individual medal.
Smith, starring in Rip it Up on West End in February, won the BBC show Strictly Come Dancing in 2012.
His career was not without controversy – in November 2016, he was granted a two-minute ban on British gymnastics after he seemed to be mocking about video in Islam. Smith said he was "deeply sorry" for his "ruthless deeds".