Watford have signed central defender Kayky Almeida from Brazilian club Fluminense.
The 19-year-old has joined the Hornets on a five-year contract and is the club's eight signing this summer.
Watford head coach Tom Cleverley told BBC Three Counties Radio on Wednesday that he was in the market for a new central defender in order to deploy a 3-5-2 formation this season.
Kayky, a natural left-footer, is not eligible to face Millwall on Saturday but could make his debut against Stoke City on 17 August.