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.
More top news
The ruling Communist Party warning its 88 million members not to play golf, likening it to "extravagant eating and drinking".
Donald Trump's press secretary will hold his first full briefing today after a weekend in which the administration clashed with the media.
Police have confirmed "several firearms" were being used on the set in Australia when a man, who was in his 20s, was shot and killed.