Will Hughes and Etienne Capoue start in midfield, while the 4-4-2 formation is completed by the presence of attacking duo Gray and Deeney.
Anthony Knockaert, Dale Stephens and Pascal Gross are part of a five-man midfield that will provide support up top to English forward Glenn Murray, who has shaken off back and neck knocks to earn a starting place.
Watford: Foster; Holebas, Kabasele, Cathcart, Janmaat; Pereyra, Doucoure, Capoue, Hughes; Deeney, Gray
Subs: Gomes, Prodl, Mariappa, Femenia, Masina, Sema, Success
Brighton & Hove Albion: Ryan; Bruno, Dunk, Duffy, Bernardo; Knockaert, Stephens, Propper, March, Gross, Murray
Subs: Button, Bong, Balogun, Jahanbakhsh, Bissouma, Kayal, Locadia