World title contender Anthony Yarde (19-1) says his father has died after contracting coronavirus.
The 28-year-old light-heavyweight from Hackney has urged people to stay at home, saying his father had been "fit with no health issues" before becoming ill.
"I'm still in shock but maybe this can help people stay at home," Yarde posted on social media.
"The more people go out and mingle, the longer this isolation will last and the more it will spread."
The total confirmed coronavirus cases in the UK on Sunday, March 29, had reached 19,522, with 1,228 deaths.
Yarde's promoter, Frank Warren, expressed his "sincere condolences to Yarde and his family".
"Coronavirus is an issue affecting all of us, but that doesn’t make the individual casualties any less tragic," the Hall of Fame promoter said.
"We hope that his fans listen to Anthony’s heartfelt plea for people to take the government's advice seriously so we can try and minimise the suffering of others."
Yarde's next fight was set to be against Britain's Lyndon Arthur on 11 April, but the event has been delayed until 11 July because of the pandemic.
BBN would like to extend their heartfelt condolences to Anthony and his family at this difficult time.