Martin Clunes, Eddie Izzard, Imelda Staunton and Bill Turnbull are due to take part in an attempt to set a world record for the largest virtual tea party.
The celebrities will be joining forces with members of the public on National Tea Day to help raise funds for the Guide Dogs charity.
Participants will be asked to share a photo of themselves enjoying a cup of tea alongside a cake or biscuit recipe.
Doc Martin star Clunes said: “The charity Guide Dogs does such incredible work year-round supporting people with sight loss, and that work is more important than ever now.
“I know I’m finding lockdown hard enough to deal with, but for people with sight loss, social isolation can be there every day.
“That’s why I’ll be raising a cup and supporting Guide Dogs.
“I hope many others will join me to raise lots of money and hopefully achieve a Guinness World Record.”
Those taking part in the world record attempt are being asked to donate the price of a cup of tea to help the charity continue its work.
The fundraiser is taking place on Tuesday April 21 between 3pm and 4pm.
Pam White, fundraising manager at Guide Dogs, said the charity has experienced a drop in its income during the coronavirus pandemic.
She added: “Donating the cost of your cuppa on National Tea Day will ensure people with sight don’t feel alone now and in the future.”