Loud moaning was heard while Gary Lineker presented the third-round replay between Wolves and Liverpool.
A confused Linkeker started chuckling after the persistent noise began, telling viewers “I don’t know who is making that noise” before continuing with his coverage.
He later shared a photo of an old mobile to his Twitter account, telling fans, “Well, we found this taped to the back of the set. As sabotage goes it was quite amusing”.
The BBC Press Office then shared a statement apologising to viewers.
“We apologise to any viewers offended during the live coverage of the football this evening,” the statement reads.
“We are investigating how it happened.”
Twitter users have commented how amusing the issue was, with some praising Lineker for how he handled the surprise on air.
Speaking about the incident on BBC Two’s Newsnight later on Tuesday night, Lineker said that he initially thought a video had been sent to one of the pundits’ phones.
He said that when he realised the sound was “too loud” to be coming from a phone he knew the incident was some kind of prank.
“If you told me this morning that tonight I’d be on Newsnight talking about a porn scandal l would have been terrified,” Lineker said.
“As pranks go, it was a good one.”