Watford have agreed a deal to sign striker Ashley Fletcher.
The 25-year-old scored 28 goals in 108 appearances for Boro after signing from West Ham for £6.5m in July 2017.
A former Manchester United youth player, Fletcher only scored one league goal last season in an injury-hit campaign, but was Middlesbrough's top scorer the previous season with 13.
Watford have also signed Imran Louza, Mattie Pollock and Kwadwo Baah this summer.
