Everton have said they are "appalled" at striker Moise Kean after he posted videos of himself and friends throwing a party at his apartment.
The videos obtained by the Daily Star, which were posted on a private Snapchat group, show Kean and others violating government regulations on social distancing amid the coronavirus pandemic.
UK government guidelines state that all gatherings should be avoided to help prevent the spread of Covid-19.
"Everton Football Club was appalled to learn of an incident in which a first-team player ignored government guidance and club policy in relation to the coronavirus crisis," a club statement said.
"The club has strongly expressed its disappointment to the player and made it clear that such actions are completely unacceptable.
"Everton has regularly stressed the importance of following all the government guidelines - including rules and advice for inside and outside of the home - through a series of official communications to all staff members, including players.
"The amazing people in the NHS deserve the utmost respect for their hard work and sacrifice. The best way to show them respect is by doing everything we can to protect them."
Kean, 20, arrived at Everton last summer from Juventus in a €32 million (£29m) deal, with the Italy international considered one of the top talents in Serie A.
The forward showed major potential with Juve in 2018-19, scoring seven goals in just 661 minutes of action.
Though the deal appeared to be a major coup for the Toffees, Kean has struggled to adjust to the Premier League in his first season in England. The striker has a return of just one goal from 26 total appearances in 2019-20, making just seven starts.
Kean's struggles were on full display at Old Trafford in December, when interim boss Duncan Ferguson substituted the Italian international only 19 minutes after bringing him on as a substitute against Manchester United.
Prior to the Premier League's hiatus due to the coronavirus crisis, Everton were in 12th place in the table. After a difficult start to the season under Marco Silva, the Toffees appointed Carlo Ancelotti as manager in December.