David Cameron has blamed getting his favourite football team wrong on "brain fade".
The Prime Minister said he supported West Ham United during a speech in south London when he is in fact an Aston Villa fan.
Outlining his 2020 vision for black and ethnic minority communities, he told supporters: "This a country where people of all faiths, all colours, creeds and backgrounds can live together in one place.
"We are a shining example of a country where multiple identities work.
"Where you can be Welsh and Hindu and British, Northern Irish and Jewish and British, where you can wear a kilt and a turban, where you can wear a hijab covered in poppies.
"Where you can support Man Utd, the Windies and Team GB all at the same time.
"Of course, I'd rather you supported West Ham."
Asked to clarify his loyalties after his speech, which he read from an autocue, Mr Cameron replied: "I had what Natalie Bennett described as a brain fade.
"I'm a Villa fan ... I must have been overcome by something ... this morning.
"But there we are, these things sometimes happen when you are on the stump."
The two football teams play in the same colours but that is where the similarities end.
When he was first elected to Parliament in 2001, Mr Cameron said he did not follow football, telling the House of Commons in a debate on hooliganism that year: "Many of those who have spoken in the debate or have written about the subject are either lawyers or football fans, but I have to confess that I am neither."
The first mentions in the national press of Mr Cameron's liking for the club came after he was elected Tory leader in 2005. He was reported in 2006 to have written on his blog that he "half-heartedly" supported Villa and could name only three of their players. His uncle Sir William Dugdale, who died last year, was the club's chairman from 1975 to 1982.
Does he support Villa?
Mr Cameron was asked about the slip-up, trending as #villagate on Twitter, in an interview with Sky News' Murnaghan to be broadcast on Sunday.
Asked to confirm which team he actually supports, he said: "I've been an Aston Villa fan all my life, I literally opened my mouth and I was going off-piste about the fact that in Britain you can be a supporter of the West Indies, a supporter of Manchester United, and a supporter of Team GB.
"I was then busking about other things you can support and was ... I don't know what happened to me, it was just one of those things."
Asked if it was on the script, he said: "No, it wasn't on the script, I was going off-script to add to the examples, and I suppose it is just the campaign. By the time you have made as many speeches as I have on this campaign all sorts of funny things start popping out of your mouth."
Asked if he remembered watching Aston Villa beat Bayern Munich in the European Cup final as a child, he said: "I do, that's why I became a Villa fan."
Pressed to say when it was, he replied: "I'm not doing quiz time because I'll get them all wrong, but that's not what I'm here to talk about.
"That's why I became a Villa fan, because my uncle was involved in the club, and back in the early 80s, with all those successes, and Andy Gray and Brian Little, and that's what got me going.
"But I don't go very often, in fact I haven't been for years and years, but I try and keep up, and I'm hoping we are going to escape the relegation zone, which we're out of now, and obviously the FA Cup final is very exciting."
Reminded of his comment in 2001 in the House of Commons that he wasn't actually a football fan, Mr Cameron said: "I mean, I'm not a regular attender, I used to play football as a kid, my son plays football, and I try and sort of keep up with what's happening in the Premier League and see how Villa are doing."