Student wizard Harry Potter and weight-obsessed Bridget Jones do not have much in common, but both are caught up in Comic Relief's red nose fever.
Harry Potter's creator JK Rowling and Helen Fielding, who wrote the Bridget Jones diaries, have put pen to paper to produce short stories for the charity.
The books are being sold for £2.50 each, with £2 profit going to charitable projects at home and abroad to coincide with Red Nose Day on March 16.
Rowling has written Fantastic Beasts And Where to Find Them, a book Harry bought to prepare him before he went to Hogwarts School.
She also penned Quidditch Through The Ages, a library book that Harry uses to learn the rules of the school's now infamous sport. Invented in the 11th century, it involves teams on broomsticks playing with four balls to make things more interesting.
Rowling says: "When Comic Relief asked me to write something, I thought I would just love to write the two books.
"There is something wonderful about the idea that laughter should be used to combat real tragedy and poverty and suffering and it is just the most wonderful thing."
Fielding's offering is Bridget Jones's Guide to Life, where the hapless Bridget offers top tips on how to give the perfect dinner party, handle all accounting and, of course, never put on a pound in weight.
After the success of her two Bridget Jones diaries, Fielding was keen to help Comic Relief. She says: "I was honoured. I have been more than lucky with Bridget and was more than pleased to help."
The books will be sold in supermarkets and bookshops across the country, with publishers, printers, type-setters and retailers all offering their services for free or at a discount.