In news that will rock the very foundations of the mixed martial arts world it has been announced that UFC 183 headliners Anderson Silva and Nick Diaz have both failed drugs tests.

The biggest shock comes with the news that Silva tested positive for Drostanalone, an anabolic steroid, and another banned substance Androsterone in an out-of-competition test administered by the Nevada State Athletic Commission on January 9th.

Meanwhile, in less surprising news Diaz tested positive for marijuana metabolites during a post-fight drugs test for the third time in his career.

Silva on the other hand has never before failed a drugs test before and neither had there been any prior suggestion that the Brazilian superstar may have been on performance enhancing drugs despite a long career at the very summit of the sport.

The 39 year-old was however enduring the toughest spell of his career, spending over a year out on the sidelines due to a broken leg he’d suffered during a title rematch with Chris Weidman at UFC 168 in December of 2013.

His recovery process was long and arduous, yet Silva was widely praised after vowing that he would return to fight another day.

He proved to be a man of his word, but while he emerged victorious on Saturday night via unanimous decision today’s revelation threatens to tarnish his reputation as arguably the greatest MMA fighter of all time.

Read the UFC’s official statement regarding Silva’s failed drug test below.

”On February 3, 2015, the UFC organization was notified by the Nevada State Athletic Commission that Anderson Silva tested positive for Drostanolone metabolites on his Jan. 9 out of competition drug test. UFC’s understanding is that further testing will be conducted by the Commission to confirm these preliminary results. Anderson Silva has been an amazing champion and a true ambassador of the sport of mixed martial arts and the UFC, in Brazil as well as around the world. UFC is disappointed to learn of these initial results. The UFC has a strict, consistent policy against the use of any illegal and/or performance enhancing drugs, stimulants or masking agents by its athletes.”

Silva will now face a disciplinary hearing with NSAC on February 17th with a nine month suspension from fighting the most likely punishment.

The former long-time middleweight champion had left his fighting future in the balance post-fight at the weekend, stating that he would speak to his family, who were eager for him to hang up his gloves, before making a decision.

He was however just about to begin coaching The Ultimate Fighter: Brazil 4 opposite Mauricio ‘Shogun’ Rua and it’s unclear whether he’ll still be taking on that role in the wake of today’s breaking news.