Named the Rebel Whopper, the new burger is made from soy but isn't suitable for vegans or vegetarians due to the way it is cooked - on the same grill as the meat burgers.
Because of this, the fast food chain is aiming the Rebel Whopper at 'flexitarians', people who eat meat but are cutting down and following trends such as 'meat-free Mondays'.
Burger King marketing director Katie Evans said: "This really is a game changer - we wanted our first plant-based Whopper to replicate the indulgence and flame-grilled taste of the real thing as closely as possible, and we're thrilled with the result.
"We're delighted to satisfy the demand for this highly-anticipated product and finally bring the Rebel to the UK."
The soy patty is made with the Vegetarian Butcher meat substitute and is served with tomatoes, lettuce, mayonnaise, ketchup, pickles on a seeded bun.
Toni Vernelli, international head of communications and marketing at Veganuary, said: "For all of the important issues that Veganuary - and most vegans - are trying to address through their food choices it makes absolutely no difference whether the plant-based patty is cooked separately or on the same grill as the meat.
"What does make a big difference to animals and the planet is when non-vegans choose a plant-based menu option, enjoy it and then order it again.
"And that's exactly who Burger King's plant-based Whopper is aimed at, flexitarians who want to reduce their meat consumption for health or environmental reasons, or are considering going vegan."
The Rebel Whopper, already available in Ireland, goes on sale to anyone in the UK with the Burger King app from Monday 6 January, and to everyone from Wednesday.
