Ben Cook has resigned as President of Atlantic Records U.K., citing rumors and repercussions of Inappropriately dressing as a member of Run-DMC seven years ago at a birthday party.

“Late last year, rumours began to circulate about my appearance at that event, many of which are simply untrue,” Cook wrote in his resignation letter. “While my intention was to honour a musical hero, I recognise my appearance was offensive and I made a terrible mistake.

“As a consequence of this, I readily agreed to disciplinary actions by my employer last year. Since then, however, allegations surrounding the party have continued to be made against me. Moreover, they have been used against a wonderful company and the label I love. I have therefore come to the conclusion that I should make this statement and step down, with immediate effect.”

Warner Music Group confirmed that this will be Cook's last week in the office, and sources said Parlophone Co-President Mark Mitchell will take on the leadership of the label on an interim basis.

Cook, initially hired to restart Asylum in Blighty in 2007, was named President of Atlantic U.K. in April 2014. He has significantly grown the label with the successes of Brit acts Ed Sheeran, Rudimental, Clean Bandit, Jess Glynne, Anne-Marie, Plan B, Rita Ora and Charli XCX, as well as U.S.-based artists including Bruno Mars, twenty one pilots and Cardi B.

In his letter, Cook wrote, “I am devastated that this mistake has caused upset and has called into question my commitment to diversity, equality and inclusion, values which I have championed throughout my career. I have learned a great deal from this event and will resolutely continue to champion these values moving forward.

“It has been an incredible privilege to have worked with the immensely talented artists, managers and team at Atlantic and the wider Warner family.

“I unreservedly apologise to anyone who has been hurt.”