Kyle Walker faces disciplinary action from Manchester City after reportedly breaking lockdown rules by hosting a party involving two sex workers.
Walker, 29, has apologised and urged people to "stay home, stay safe" during the coronavirus pandemic.
In a statement, City said the England defender's actions had "directly contravened" his responsibility as a role model.
It added that the club would be holding an investigation.
The government has put social distancing restrictions in place to combat coronavirus. As of 09:00 BST on Sunday, 47,806 people had tested positive for coronavirus in the UK, with 4,934 deaths.
City said: "Manchester City FC are aware of a story in a tabloid newspaper regarding the private life of Kyle Walker in relation to a breach of the UK lockdown and social distancing rules.
"Footballers are global role models, and our staff and players have been working to support the incredible efforts of the NHS and other key workers in fighting the effects of the Covid-19 coronavirus in any way we can.
"Kyle's actions in this matter have directly contravened these efforts.
"We are disappointed to hear the allegations, note Kyle's swift statement and apology, and will be conducting an internal disciplinary procedure in the coming days."
Last Wednesday, Walker posted on social media, urging the public to follow government guidelines on social distancing by staying indoors.
In a statement responding to the reports of a party at his house, he said: "I want to take this opportunity to issue a public apology for the choices I made last week which have resulted in a story today about my private life in a tabloid newspaper.
"I understand that my position as a professional footballer brings the responsibility of being a role model. As such, I want to apologise to my family, friends, football club, supporters and the public for letting them down.
"There are heroes out there making a vital difference to society at the moment, and I have been keen to help support and highlight their amazing sacrifices and life-saving work over the past week.
"My actions in this matter are in direct contrast to what I should have been doing regarding the lockdown. And I want to re-iterate the message: stay home, stay safe."
Walker is the second high-profile Premier League player to express his regret for breaking government guidelines on social distancing.
Aston Villa captain Jack Grealish apologised after being pictured at the scene of a car accident, hours after he posted a video urging fans to stay safe at home on social media.
Grealish was fined and disciplined by his club, with the proceeds donated to the University Hospitals Charity in Birmingham.