Stars including Bono and One Direction gathered in London on Saturday (15Nov14) to record a new Band Aid single as it emerged Bob Geldof has re-written the lyrics to Do They Know It's Christmas? for the special fundraiser.

The Boomtown Rats rocker is recreating his 1984 stunt, when the song was recorded in 24 hours with vocal contributions from the most famous pop stars of the day, before being rush-released.

U2 frontman Bono, who performed on the original hit, was in a London recording studio on Saturday and was due to be joined by a host of other stars including Chris Martin, One Direction, Adele, Ed Sheeran, Sinead O'Connor, Rita Ora, Ellie Goulding, Sam Smith, and Paloma Faith.

They will record a new version of Do They Know It's Christmas? to mark its 30th anniversary by raising money for the victims of the Ebola outbreak in West Africa, and it has emerged Geldof has tweaked the lyrics to his song to fit the occasion.

Most notably, the track's famous line "Well tonight thank God it's them instead of you" - sung by Bono on the original - has been changed to "Well tonight we're reaching out and touching you".

The lyric "Where the only water flowing is the bitter sting of tears" has been replaced with "Where a kiss of love can kill you and there's death in every tear".

As the project gathered pace on Saturday and more stars continued to arrive at Sarm Studios - where the original Band Aid was recorded - Britain's Chancellor of the Exchequer George Osborne confirmed to Geldof he will waive the collection of Value Added Tax (Vat) on the record.

The song will get its first airing on U.K. talent show The X Factor on Sunday night (16Nov4) before being made available to download on Monday (17Nov14). It will be released on Cd in December (14).

Speaking outside the studio on Saturday, Geldof says, "I've just spoken to the Chancellor George Osborne and he's said we can have all the Vat back on the record. So 100 per cent of any income from this record, no tax whatsoever. If the government is prepared to do that, then come Monday at 8am when every station plays this track across the nation, buy this thing. Don't go looking for it free. Buy it."

Arriving at the studio, Bono told reporters he was running late because his flight had been delayed due to heavy fog, and joked he is having bad luck with planes following an earlier incident this week (beg10Nov14) when a rear door of his private jet sheared off during a journey to Berlin, Germany.

He says, "I just feel really embarrassed to be late. Not having a lot of luck with airplanes at the moment. It was fog."

One Direction star Niall Horan urged fans of the band to buy the single on its release, adding, "Hopefully it gets to number one and raises a lot of money for a really worthy cause."

Geldof said he was inspired to raise money to fight Ebola as victims in West Africa are dying because "they're extremely poor, which is radically unacceptable. It makes me sick and makes me angry."

The original Band Aid single raised $12.8 million (£8 million) for famine relief in Africa in 1984. It has been re-recorded for charity twice since then - in 1989 and 2004.