Burger King is offering all customers a free Whopper for a limited time

All Burger King customers have the chance to pick up a Whopper for themselves absolutely free of charge.

The popular fast-food chain has launched the special offer in the run-up to Halloween with its app's 'limited edition ghost detecting feature'.

Then again who cares about finding ghosts on an app when you can use it to find a free burger instead.

Well, we say free but it's actually a buy-one-get-one-free offer, you can't just walk into a Burger King and demand they give you a Whopper for nothing, not legally anyway.

If you want to get your free Whopper then first things first you'll need the Burger King app, which you can download for diddly squat.

Then you use the 'Home of the Ghosts' feature on the app and track down a ghost (what a way to find out ghosts are real), which gets you a buy-one-get-one-free deal on Whoppers which you can use with a click and collect order.

One of the burgers is for you and the other is for the ghost, but since they're dead, don't need food and are notoriously non-judgmental you can scoff it with no guilt.

Kristoffer Tripplaar / Alamy Stock Photo

Since this is a Halloween offer it runs out at one minute to midnight on 1 November, at which time all the ghosts in the world disappear and stop dispensing your phone with offers for free burgers.

It's also only one free burger per person, so you can't spend the next couple of weeks running around chasing ghosts for the free Whoppers.

You can either pick up a classic Whopper, or go for a plant-based version of the burger if you'd prefer one without any meat in it.

Sadly for those whose preferred Burger King locations are to be found at train stations, airports, holiday parks or motorway service stations, the offer doesn't apply to those outlets.

Erkan Mehmet / Alamy Stock Photo

If you've never actually tried a Whopper, it's a beef burger topped with tomatoes, lettuce, pickles, onions topped with mayonnaise and ketchup all housed in a sesame seed bun.

Those who already have the Burger King app will be familiar with that episode back in August when it randomly sent a load of people a blank receipt in the middle of the night.

A whole load of people ended up getting pretty freaked out about this, though maybe it was the work of the ghosts Burger King seems so keen for you all to catch.