Chelsea winger Willian has instructed his lawyers to take legal action over a "forged" letter purporting to authorise a change of agent.
The Brazil international shared the document on Instagram on Thursday with a statement denouncing its authenticity.
The letter, which Willian says has been "circulated through the football market", claims to sanction a change in his representation until August 15.
"I would like to clarify that I never signed such letter, the content of which I completely deny," Willian wrote on Instagram.
"Finally, since there seems to be clear evidence that my signature has been forged, or anyway misused, I hereby inform that my lawyers are already instructed to proceed with all appropriate legal measures before any competent courts or authorities.
"I hope I have clarified the matter and any possible misunderstanding."
In the recent days I have been informed that a “letter of authorization for player agent FIFA”, allegedly signed in my name has been circulated through the football market. In such letter, Mr. Denirobson Dias would grant an authorization to Mr. Renee Pinheiro Anunciação to represent me until 15 August 2018, throughout football clubs in the United Kingdom and France. I would like to clarify that I never signed such letter, the content of which I completely deny. Finally, since there seem to be clear evidence that my signature has been forged, or anyway misused, I hereby inform that my lawyers are already instructed to proceed with all appropriate legal measures before any competent courts or authorities. I hope I have clarified the matter and any possible misunderstanding. Willian Borges da Silva Nos últimos dias fui informado de que uma “carta de autorização para agente de jogadores FIFA”, supostamente assinada por mim, está circulando pelo mercado do futebol. Na referida carta, o Sr. Denirobson Dias concede uma autorização ao Sr. Renee Pinheiro Anunciação para me representar até 15 de agosto de 2018, perante os clubes do Reino Unido e França. Gostaria de esclarecer que nunca assinei tal carta, cujo conteúdo nego completamente. Finalmente, uma vez que parece haver provas claras de que a minha assinatura foi falsificada, ou de qualquer forma mal utilizada, informo que meus advogados já estão instruídos a proceder com todas as medidas legais cabíveis perante quaisquer tribunais ou autoridades competentes. Espero ter esclarecido o assunto e qualquer possível mal-entendido. Willian Borges da Silva
Willian's future has been a point of speculation for most of the summer, as Barcelona were believed to have made multiple bids for the attacker.
Though that pursuit ended with the La Liga champions signing of Willian's Brazil countryman Malcom from Bordeaux, reports suggest both Manchester United and Real Madrid remain interested in his services.
A delay in his arrival to Chelsea from his World Cup holiday prompted speculation that he had been subject to a bid, but Goal understands a passport issue was the cause.
However, Chelsea manager Maurizio Sarri admitted unhappiness over the situation, and promised talks with the winger in the coming days.