Gary Lineker appeared to be shocked after "checking out" Daniel Kinahan.
The Kinahan "cartel boss" was recently praised by boxing champion Tyson Fury, who said the Dublin man had a major role in securing a two-fight deal between himself and Anthony Joshua.
Match of the Day presenter Lineker initially tweeted "yes" after the announcement was made.
However, social media users urged the former England striker to research Kinahan's background.
Lineker said: "Never heard of him (Kinahan) . Will check him out."
He later added: "Crikey... just done some reading [shocked emoji]."
The TV host subsequently removed his initial tweet.
Meanwhile, Kinahan has been called out as a crime cartel boss, on the floor of the Dáil, who is trying to "re-brand himself as a boxing promoter".
And Alan Kelly has called on the Taoiseach to “intervene” after gangland chief Mr Kinahan was lauded as a successful international boxing promoter this week.
The Labour leader told the Dáil that people in the boxing and sports TV industries need to know about Mr Kinahan’s sick legacy ahead of the huge boxing match between Joshua and Fury in the UAE that he is promoting.
Kinahan has been publicly credited by Fury for getting him the multi-million dollar fight with fellow heavyweight champ Joshua this September.
But Mr Kelly said the country “owes it to the victims of the cartel” to let the international sporting community know the history of Mr Kinahan, one of Ireland’s most notorious criminals.
Taoiseach Leo Varadkar in reply told Mr Kelly that he has been in touch with the United Arab Emirates (UAE) authorities to warn them about the promoter’s dodgy past.
Mr Kinahan has suddenly shot to the top in international boxing promotion after heavyweight boxing champ, Mr Fury, name-checked him as the man who’s making his upcoming world title fight in the UAE happen.
