Thompson signed his first professional deal at Watford in November
Northern Ireland international Adam Thompson has joined Brentford on a one-month loan from Watford.
The 18-year-old defender, a product of Watford's youth academy, has twice played his country at senior level.
Thompson has appeared 11 times for the Hornets, following his debut against Notts County last year.
Manager Uwe Rosler told the club website: "He's represented his country and played in the Championship and will be a very good addition to the squad."