The 100 and 200 metre world record holder quit athletics a year ago and is now on trial with Australian football club Central Coast Mariners as he looks to achieve his new dream of becoming a professional footballer.
"So guys, I've retired from track and field looking to become a footballer but look at this", said Bolt, before showing the letter on the video.
"So I asked the lady, 'So why am I getting drug tested if I haven't signed for a club yet?' And she said they told her that all elite athletes have to get tested".
The Jamaican, who previously trained with Absa Premiership side Mamelodi Sundowns as well as Bundesliga club Borussia Dortmund, has made no secret of his aspirations to play professional football.
"If they get to that (signing) point then we'll look at what's feasible for us but it can't be for the marquee player fund", he said.
On Friday (October 12) Bolt scored twice in a pre-season friendly against Macarthur South West.
It's no secret that Usain Bolt has been trying to make it as a footballer since retiring from Athletics in 2017.
Though his goals certainly caught the world's attention, his football skills still leave a lot to be desired.
Meanwhile, NAIJ.com had earlier reported that Usain Bolt was in the best form of his life scoring two goals for Central Coast Mariners in a trial match against Macarthur South West United.
The eight-time Olympic champion, who dominated sprinting after taking double individual gold at the Beijing Olympics in 2008, is now bidding to become a professional footballer.
The move is just one of a number of offers Bolt is considering, with the Mariners deciding whether to keep him on for the 2018-19 A-League season.