In what's planned to be the first of an annual event, Shake Shack are teaming up with Action Against Hunger to both give money to charity and give away free shakes. Throughout August, if you donate £2 to the charity as part of your order, you'll get a voucher for a free shake on your next visit - worth £5.
This sounds like a no-brainer to us. Get one of the best burgers in town, donate to a good cause AND get something back for your trouble.
The Great British Shake Sale will be at Shake Shack Covent Garden, from August 1-31st. For more information, follow them on Twitter @shakeshackUK.