Imelda Staunton and Jim Carter are set to host a lockdown quiz featuring questions on Harry Potter and Downton Abbey.
The online game, which takes place on Thursday, is raising money for Marie Curie.
Staunton, who played Dolores Umbridge in the Harry Potter films, and her husband Carter, who starred as Charles Carson in TV series Downton Abbey, will ask questions about the two stories.
Carter said that the pair might “be bribed into slipping into character” during the quiz.
He added: “I think we have a plan that if people donate a certain amount then Mr Carson and Dolores Umbridge’s voices could appear and people could get some shout outs from us.”
Carter said that not all the questions will be about the stories, adding: “You don’t have to be a Harry Potter or a Downton Abbey geek to be able to enjoy it – it really is for everybody.
“So the idea is that this will just be some fun, I have done a lot of quizzes over the years for charities and fundraisers, so I think even if you don’t get the answers right, you have to enjoy the questions, so we will give lots of multiple choices to give people a chance to have a guess at the right answer.”
The quiz will take place on Thursday at 8.15pm and can be accessed via Marie Curie’s Facebook page.