Pokémon is big business at the moment, with this year's launch of Pokémon GO adding even more momentum to a franchise which has been a money-spinner since its inception in the '90s.

The mobile app has had quite an impact on the value of certain Pokémon playing cards, in particular the Japanese "Pikachu Illustrator" promo card which was given away in a competition back in 1998. One of these cards has just sold for a world record $54,970 during a public auction held by Dallas-based Heritage Auctions in Beverly Hills, California.

Barry Sandoval, Director of Operations for Comics at Heritage Auctions, explains what makes this card so special:

The Pikachu Illustrator Card was given in January of 1998 to winners of the CoroCoro Comic Illustration Contest. Only 20-39 copies of this card were released, 10 of which are graded in top condition and it is unknown how many still remain with the public.

Sandoval states that the Pikachu Illustrator card had previously sold for around $23,000 in the early 2000s. Illustrated by Atsuko Nishida - one of the chief Pokémon graphic illustrators - the card showcases the famous Pikachu, who is holding drawing equipment, hence the card's name.

In the unlikely event you have one of these sitting at the bottom of your sock drawer, now might be the time to cash it in.