A message from Japanese billionaire Yusaku Maezawa has become the most retweeted tweet of all time.

Maezawa took to Twitter on Saturday to give 100 randomly selected retweeters the chance to win a share of 100 million Japanese yen ($923,000).

Twitter users were given until Monday to follow Maezawa's account and retweet the promotion to be in with a chance of scooping the prize. His tweet has now been shared almost 5 million times.