Mrs Brown is donating the turkey to The Connection at St Martin-in-the-Fields, a charity which helps homeless people of all ages. She promised: "This bird will be cooked at the charity's day centre and will help some less fortunate people enjoy a traditional British turkey this Christmas."
The turkey was presented on behalf of the British Turkey Federation by Essex farmer Paul Kelly, whose KellyBronze turkeys are considered by many as the Rolls Royce of Christmas turkeys.
Kelly, who this was earlier this year named British Turkey Man of the Year by the industry, said: "Demand for our turkeys this year is as great as ever. We are delighted to see turkey is still the No 1 choice for the majority of families."
The presentation of a British turkey to Downing Street dates back to the days when Sir Winston Churchill was Prime Minister. Along with the Browns, 20 million families will be tucking into turkey this Christmas.