The Bank of England has released the new £20 note into circulation today, 20 February 2020.
The note's design features a self-portrait of painter JMW Turner and celebrates the contribution of the arts to British culture.
According to the Bank, the new note will be its 'most secure banknote yet'.
Read on to find out what makes it different, what to do with your old £20 notes and how to spot a rare new or old £20 that could be valuable.
Unveiled at the Turner Contemporary gallery in Margate last October, the new note features a self-portrait of JMW Turner, the 18th and 19th-century British artist known for his vivid landscape and marine paintings.
Beside him, there is an image of the HMS Temeraire, a ship from one of Turner's most iconic works. Below Turner's signature is the quote 'Light is therefore colour', taken from a lecture he gave on the arts.
The note design also includes an image of the Turner Contemporary gallery, and of the nearby Margate Lighthouse.
The new £20 follows the £5 and £10 notes in shifting from paper to polymer. These plastic notes are believed to be more secure, according to the Bank of England.
Sarah John, Chief Cashier of the Bank of England, said: 'The evidence is that counterfeiters find it much more difficult to produce counterfeits on polymer.
'In other countries where they have moved to polymer notes, there have been some examples, but we have yet to see in the UK any really good attempts at counterfeiting polymer banknotes.'
She described the new £20 as the 'most secure banknote yet'.
The note features foil in two different colours, with the Turner Contemporary gallery in blue, and Margate Lighthouse in gold. There's also a second polymer window in the right-hand corner, in the shape of a window from Tintern Abbey, which Turner painted.
Ms John said: 'Those features make it much more difficult to counterfeit, even than our existing polymer notes.'
Even though the new notes have entered circulation, you can still spend your old notes.
The Bank of England hasn't yet set a date to withdraw legal tender status from paper £20 notes, as it did with the paper £5 and £10 notes.
The Bank will give six months' notice before it withdraws the old notes. So until the withdrawal date is announced, you definitely have more than six months left to use them.
After that, you will no longer be able to spend them in shops. They won't be worthless, though. Each note will hold its value, and you'll be able to take or send them to the Bank of England to exchange for new ones.
If they're treated the same way as paper £5 and £10 notes, you'll be able to pay them into your bank account at some high street branches and at Post Offices.
As for where your old paper notes will end up, the Bank of England says they're either composted into a soil improver or processed at a local energy recovery facility to generate electricity.
The £20 notes will be the third polymer notes to enter circulation, following polymer £5 notes in 2016 and polymer £10 notes in 2017.
Polymer £50 notes are expected to follow the £20 notes in 2021.
Polymer notes are meant to last at least 2.5 times longer than paper notes. When they do deteriorate, they can be recycled into things such as plant pots and tool trays.
The reason: production waste. Every £20 note has to be exactly the same to make it easier to spot a fraud. If any are produced with slight flaws, they have to be sent straight for recycling.
Stream the episode below to hear more from 'behind-the-scenes' of the new £20 note and how millions of notes have already been destroyed.
Even when the Bank does withdraw paper £20 notes, you might be better off keeping some of them. If you have the right notes, collectors might be willing to buy them off you.
Indeed, as you start to get new £20 notes it's also worth checking if you've got one that might become sought after.
Most £20 notes will not fetch more than £20, but some special specimens are considered highly desirable.
While there's no guarantee your notes will ever be worth more than face value, here are the things to look out for.
Many banknote enthusiasts are interested in serial numbers, which are found in one of the bottom corners of the note. If the number is special in some way, you might be in luck.
Sequential or matching numbers, such as 123456 or 222222, might catch a collector's eye.
Serial numbers with multiple eights can be popular due to the number's association with luck in some Chinese communities. Another 'unique' serial code is AK47, like the famous military rifle.
The higher the serial number, the later the note was printed.
If you manage to get the last paper £20 made ever , collectors might be interested in adding it to their collection.
Notes with lower serial numbers usually sell for the most money.
Since the numbers reset whenever a note's design changes, the new polymer £20 will give you another chance to find a low one.
It's unlikely you'll find a note this low, though, as the first notes are often given to dignitaries, such as the Queen and Prince Philip.
The note that sold for £16,800 was originally given to chancellor Anthony Barber in 1971.