Bob Geldof has urged fans to take part in the Band Aid Challenge.

The Boomtown Rats frontman is hoping to raise more money for Ebola relief with a social media effort similar to the Ice Bucket Challenge - which saw web users pour freezing water over themselves before nominating three people to do the same to raise awareness of ALS - that involves singing a key line from the re-written Band Aid 30 version of 'Do They Know It's Christmas Time?'.

Fans are asked to download the WholeWorldBand app and, using its inbuilt camera and microphone, sing Bono's like ''Tonight we're reaching out and touching you'' and then nominate three people to do likewise and posting the videos on social media.

Bob said: ''I've got a bunch of celebs lined up who are going to do it. We need to keep up momentum. I want us to raise about £5 million but we need people to understand that we've only got three weeks to make a difference.''

The app can automatically create a video mix featuring the Band Aid 30 artists plus up to five other people singing along.

Each new mix can be shared on YouTube, Facebook and Twitter and for every singer participating, £1.40 will be collected for the Band Aid 30 appeal .