Louis had appeared in footage that showed him laughing and saying an Islamic phrase while his friend and fellow gymnast Luke Carson pretended to pray beside him. The video received a backlash online and many criticised Louis for mocking the religion - with some alleging the video could be deemed as 'racist.'
The 27-year-old has now taken to Twitter and insisted he is "deeply sorry" for his "thoughtless actions."
His apology read: "I am deeply sorry for the recent video you may have seen. I am not defending myself, what I did was wrong. I want to say sorry for the deep offence I have caused and to my family who have also been affected by my thoughtless actions. I recognise the severity of my mistake and hope it can be used as an example of how important it is to respect others at all times. I have learnt a valuable life lesson and I wholeheartedly apologise."
Reveal has contacted a rep for Louis. Luke has also publicly apologised on social media.
According to BBC Newsbeat, British Gymnastics have confirmed they will be investigating the incident.
A spokesperson for British Gymnastics has said: "British Gymnastics does not condone the mocking of any faith or religion and is appalled by such behaviours. Gymnastics is an inclusive sport and we are proud of members who portray the inclusive values of British Gymnastics. Members who break our code of conduct can face suspension or expulsion from our organisation. We will be investigating the behaviours reported."
Louis represented Great Britain at the 2016 Olympics in Rio De Janeiro for gymnastics. He finished in second place on the pommel horse, gaining a silver medal. His teammate Max Whitlock won gold.
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