Yoko Ono, Katy Perry, will.i.am and David Guetta are among the celebrities who have recorded a cover of John Lennon's 'Imagine' to raise funds for UNICEF.

Speaking at the launch of the collaboration, award-winning DJ David said: "I'm really excited to be working with UNICEF on this incredible new project. Our world version of 'Imagine' will be like no other - I am proud to be a part of this collaboration,

"We have to get the word out that every voice counts and every child counts too."

Other celebrities from the world of music, film, fashion and entertainment who feature in the track - which the charity hopes will spur the largest ever global sing-a-long - include 'Mandela: Long Walk to Freedom' actor Idris Elba, 'Friends' star Courtney Cox and 'Run' singer Nicole Scherzinger.

UNICEF has now launched an app enabling fans to share their own recording of the classic song, which can be shared across social networks to raise awareness for the campaign.

Each person who covers the track will then be in with a chance of appearing in the new UNICEF version of the track which will be produced by David and released in the lead up to New Year's Eve 2014.

Funds raised through the #IMAGINE project will support the organisation's programmes providing education, nutrition, healthcare and immunisations, clean water and sanitation, protection and emergency relief for children in more than 150 countries and territories.