IT'S time to dust off those shelves and see if you already own a book which could be worth a fortune.

Experts from have researched and revealed seven books that have been sold for hundreds or thousands of pounds and are now urging households to check if they unknowingly own similar copies.

The first edition of the first book in the Harry Potter series – Harry Potter and the Philosopher’s Stone – has been known to fetch between £30k-£40k at auction, but only a few thousand copies were printed.

And even first editions of rom-com favourite Bridget Jones’s Diary could be worth as much as £500 if signed by the author.

A spokesperson for The Money Pig said: “Bookworms will likely have hundreds of books in their collection, and this means the chance of owning a valuable copy is even higher.

“Other households might have piles of books that have been left discarded in the attic, so it’s worth checking that you’re not sitting on what could be a pretty significant cash cow.

“First editions of many books – both modern and classic – will almost always be worth more than later editions, and if they’re signed by the author, it could increase their value substantially.”

1. Harry Potter and the Philosopher’s Stone by J.K. Rowling

The first edition of Harry Potter and the Philosopher's Stone is the only book in the series that credits ‘Joanne Rowling’ as its author and a print line number that reads ‘10 9 8 7 6 5 4 3 2 1.’

First editions of Harry Potter and the Philosopher's Stone can fetch about £30,000 to £45,000 at auction, depending on its condition.

2. Bridget Jones’s Diary by Helen Fielding

Many will have a copy of this best-selling 1996 novel. A first edition of Bridget Jones's Diary could be worth £175, with a signed copy potentially selling for as much as £500.

3. The Great Gatsby by F. Scott Fitzgerald

The first edition of F. Scott Fitzgerald’s The Great Gatsby with the original dust jacket is a rare book to track down.

The novel wasn’t a best-seller when it was released in 1925, and only around 25,000 copies sold by the time of the author’s death in 1940.

However, a first edition with the dust jacket can now fetch upwards of £150,000.

4. The Hobbit by J.R.R. Tolkien

London publishers George Allen & Unwin Ltd. printed only 1,500 copies of The Hobbit for its initial run, but the children's book quickly sold out three months after its release. Since it's so limited, a first edition copy in near-perfect condition is worth about £50,000.

5. Trainspotting by Irvine Welsh

This gritty modern novel filled with heroin addiction, crime and poverty in Edinburgh can currently fetch up to around £2,700 for a 1993 first edition.

6. Animal Farm by George Orwell

A superb first edition of George Orwell’s Animal Farm – which critiques the ideology of Stalin in the Soviet Union – is worth around £7,000.

7. Lord of the Flies by William Golding

If you own a pristine first edition of Nobel Prize-winning author William Golding’s classic, you could cash it in for up to £8,000.