The Argentinian forward is looking for game time after making just seven starts for Italian side Fiorentina this season.
Watford have added to their attacking options.
Premier League outfit Watford have signed Fiorentina striker Mauro Zárate for a fee thought to be in the region of £2m.
Watford join Zárate’s list of English clubs after loan stints with Birmingham and QPR.
The 29-year-old more recently played for West Ham between 2014-2016 before moving back to Italy scoring just five goals over two seasons at the Hammers.
However, the Argentinian never managed to establish himself in Slaven Bilic’s starting eleven.
Zárate joins on a two-and-a-half year deal and is Watford’s sixth forward player in the squad.
He joins established regulars such as captain Troy Deeney and Odion Ighalo in competing for a place.
Watford currently sit in 14th place just one place below where they finished last season which saw them put in some impressive performances in particularly their 3-0 victory over Liverpool in December 2015.
Hornets boss Walter Mazzarri will be hoping the ex-Internazionale player, a club that he managed briefly during the 2013/14 season, can help them out of a slump which has seen them go without a win in the league for seven games.