Chris Martin, Lily Allen and Alesha Dixon are among celebrities urging volunteers to become "dementia friends" and help care for those with the degenerative condition.
Volunteers who take part in the scheme will be able to attend free sessions to learn how to spot the signs of dementia and offer support for sufferers, the Alzheimer's Society said.
In a new ad which will be aired for the first time tonight, the pop stars will be seen performing The Beatles' track I Get By With A Little Help From My Friends.
Other celebrities involved in the ad include comedian Simon Pegg, actor Ray Winstone, footballer Leighton Baines and presenter Paul O'Grady.
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Four Arab nations that cut ties with Qatar over its alleged support for Islamist groups have handed their neighbour a 13-point list.
The father-of-four from Cardiff with appear in court this afternoon charged with terrorism-related murder and attempted murder.
Loyalist paramilitary commander turned supergrass Gary Haggarty has pleaded guilty to 200 terrorist offences, including five murders.