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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Malta's government is offering the reward for anyone with information on who killed Malta journalist Caruana Galizia with a car bomb.
Ministers are ready to reduce the waiting time for Universal Credit payments following an outcry from Tory MPs, it has been suggested.
Storm Brian will bring strong or very strong winds across southern and western parts of the UK