Dermot O'Leary likes his bagels with salt beef and mustard with pickles on the side. Boris Johnson prefers the traditional smoked salmon and cream cheese.
The X Factor host and London Mayor are among celebrities and Jewish community personalities polled on their favourite filling by World Jewish Relief as part of the charity's Big Bagel promotion, encouraging supporters to run bagel-based events to raise money and awareness.
Seventy hosts have already signed up nationwide and will be sent themed invitations, balloons, keyrings and suggested fillings from cookery expert Annabel Karmel.
WJR backers will also be voting on its website for their favourite filling. The number one choice will be sold at Daniel's bakery in Temple Fortune with a proportion of profits going to the charity.
Fundraising director Paul Stein was "delighted to have so many celebrities and community figures on board to help WJR promote this fun event. Funds raised will make a real difference to the lives of our vulnerable clients around the world."