The singer, who is best known for his hit track ‘Pony’, was talking to retired ballerina Wayne Sleep, when he made the admission.
Sleep, who came out as gay in his 40s, told his fellow housemates that the late Queen singer had encouraged him to come out at a younger point, but he didn’t take his advice.
At this point, Ginuwine jumped in to say that he was not familiar with the rock legend.
Fans of Mercury were quick to jump on Twitter to broadcast their frustration.
“I demand immediate eviction from the BB House (and the planet tbh) of Ginuwine for not knowing who Freddie Mercury is,” wrote one.
“Ginuwine asking who Freddie Mercury was has just made me lose my faith in humanity,” said another.
Turned on #cbb last night for the first time
See that guy Ginuwine asking who Freddie Mercury is..
Won't be watching this again
— Yanni Pap ✌ (@Yanni_Pap) January 11, 2018
— 💗💓💗 (@0oGlitznGlamo0) January 10, 2018
I’m dead that Ginuwine just asked who Freddie Mercury is. #CBB
— Mike (@BigBrotherAbyss) January 10, 2018
— Krystle 🤓🌊 #Resist 🏳️🌈 (@Kryingkrys) January 11, 2018
Ginuwine entered the Big Brother house with various other male celebrities on Friday, after the series was billed as an all-female special.
Some viewers have criticised Channel 5 for adding controversial comedian Dapper Laughs to the ‘feminist’ season.
Female housemate Ann Widdecombe has also attracted controversy after being accused of “victim blaming” during a discussion about Harvey Weinstein between the housemates.