Watford are investigating an allegation of homophobic chanting at their match against Southampton on Saturday.
The incident is said to have occurred during the Hornets' 1-0 Premier League defeat at Vicarage Road.
The club said in a statement: 'We are aware of an incident of homophobic chanting at Saturday's match.
'We have spoken to the supporter who reported this and are working with them to identify the individuals responsible.
'We reiterate our zero-tolerance approach to discrimination and how to report it.'
Watford were beaten at home in Saturday's match, with Southampton forward Che Adams scoring the decisive goal.