Anthony Joshua will have a new opponent announced next week after promoter Eddie Hearn revealed Jarrell 'Big Baby' Miller has failed a second drug test.

Heavyweight champion Joshua was scheduled to defend his WBA, IBF and WBO titles against the American at Madison Square Garden on June 1.

However, Miller returned an adverse finding in a test conducted last month by the Voluntary Anti-Doping Association (VADA), putting the bout in doubt.

The New York State Athletic Commission refused the 30-year-old a boxing license following the result, though he published a statement on his Instagram account on Wednesday in which he denied ever knowingly using a banned substance and confirming his intention to appeal.

Hearn offered an update on the situation via Twitter on Friday, announcing Miller had failed a test for a "further substance", leaving him to find an alternative option for Joshua's American debut.

"We have now received news from VADA that Jarrell Miller has now failed a second seperate[sic] test for a further substance," Hearn tweeted. "AJ’s June 1 opponent will be announced next week - if you don’t think you can beat him clean then delete my number!"

Omnisport contacted VADA for confirmation of the second test result.