Willian has signed a season-long deal with Fulham.
Ex-Chelsea and Arsenal midfielder Willian, 34, had been playing with Corinthians.
However, the 34-year-old had his contract cancelled with the Brazilian club after stating he and his family received death threats on social media.
Willian told Fulham's club website: "I'm happy to be here, I'm happy to be back in the Premier League.
"Fulham is a special club, a club that wants to improve, that wants to fight for something bigger, so I'm here to help, and I can't wait to get started."
Meanwhile, back-up goalkeeper Paulo Gazzaniga departed Fulham on deadline day, joining Spanish club Girona on a season-long loan.
