Anthony Joshua will face newly-elevated world champion Daniel Dubois on September 21 at Wembley Stadium.

The title clash was made possible by formerly undisputed Oleksandr Usyk – who has beaten both of the Brits – vacating his IBF belt which saw Dubois upgraded from Interim to Full champion.

Despite both men typically being respectful in the build-up to bouts, tensions rose during their first face-to-face when young Dubois told Joshua they could fight straightaway. ‘AJ’ warned the champion that he didn’t take disrespect lightly and threatened to hit him with a chair.

The pre-fight promotion has now taken another twist in the form of Joshua’s management team, 258, sending a public message to Frank Warren’s Queensberry Promotions asking why their man Dubois hadn’t signed up for Voluntary Anti-Doping Agency testing yet.

Dubois has successfully completed VADA testing on a number of occasions, including for his previous world title challenge against Usyk, his latest victory over Filip Hrgovic and his win against Jarrell Miller, who has failed for numerous substances in the past.

It was before an ill-fated fight with Joshua that Miller first tested positive. The two-time heavyweight champion has also had a rematch against Dillian Whyte cancelled due to Whyte failing a test that was later ruled to be down to a contaminated substance. The replacement opponent, Robert Helenius, made it to fight night but news later broke he had a banned substance found, too.

The Wembley event is a Riyadh Season promotion with the help of Queensberry and Matchroom Boxing, which handles the career of Joshua. Seconds Out has reached out to Queensberry for comment.