Watford have signed Argentine forward Mauro Zarate on a two-and-a-half-year contract from Italian club Fiorentina. The 29-year-old returns to the Premier League after previous spells with West Ham United, Queens Park Rangers and Birmingham City. Zarate's former clubs also include Inter Milan and Lazio. Watford, who signed Everton midfielder Tom Cleverley on loan earlier this month, are 14th in the table, eight points above the relegation zone.