Alan Rickman, Emma Thompson and Mark Thomas have written to "express our opposition" to cuts at the BBC, including the proposed closure of 6 Music and the Asian Network.
They have put their names to a letter of protest signed by 47 others, including Bianca Jagger, the actor Meera Syal and Green party leader Caroline Lucas MP, and published in today's Guardian.
The letter comes on the closing day of the BBC Trust's public consultation on the cuts planned as part of the BBC director general Mark Thompson's strategy review.
Thompson's review proposes closing two digital radio stations, 6 Music and the Asian Network, and cutting back other areas of BBC activity, including its online operation.
"Losing services like 6 Music and the Asian Network, which have brought thousands of new listeners to the BBC, would be a huge mistake," the letter states.
"The BBC helps to keep our standards high and we shouldn't be prepared to jeopardise them with cuts. The BBC has many enemies. Media moguls who made billions from undercutting public service broadcasting would love to see it crumble. But it's vital that we don't let that happen."
Campaigners are planning a series of "flashmob" demonstrations outside the corporation's offices in seven cities today, including the BBC Trust's offices on Portland Street, central London.
There have been suggestions that the BBC Trust may reverse the closures after the public outcry.
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