- England and Wales meet Saturday
- Tickets on sale for close to $2,500
- Both sides won opening Six Nations games
(CNN)It's the hottest ticket in town -- and then some.
Six Nations clashes between England and Wales are rich in history, rarely short of drama, and ever-popular with fans, but if you haven't already got a ticket for Saturday's game it's going to cost you.
While tickets for the contest at London's Twickenham stadium are officially sold out on the England Rugby website, there has been a surge in demand this week with prices soaring on resale sites.
A seat at Twickenham Stadium is costing as much $2,430 (£1,750) on one resale site -- StubHub -- with many tickets available in the region of $500 to $850. Ticket prices originally ranged from $57 to $224, according to England's Rugby Football Union.
A StubHub spokesperson told CNN it does not set ticket prices, it is merely a marketplace where people can buy and sell.
"Higher-priced listings are often posted by new sellers taking a punt, which do not reflect the actual sale prices," said the spokesperson.
But buyers beware.
Last September, hundreds of ticket-holding fans were refused entry to a Foo Fighters gig at London's O2 Arena. At issue was that those who bought tickets from some resale sites were unable to produce ID to match the name of the original ticket buyer, according to Britain's Competition and Markets Authority.
"Innocent consumers like these are being left out in the cold -- literally -- as artists, promoters and venues act to tackle so-called ticket touts," said the CMA, which promised to take action against unscrupulous secondary ticketing websites.
'Don't risk it'
The RFU is also concerned about resale sites.
"We are out there every day, monitoring, checking and challenging the secondary market sites which are advertizing Twickenham tickets in breach of our terms and conditions," an RFU spokeswoman told CNN.
"Our message to fans is clear -- if you buy from an unofficial source, there is a very good chance you won't get in, so don't risk it."
Tickets for this year's Super Bowl LII on StubHub were reportedly going for $3,100 a few days before the game. Other big players in the resale industry include Viagogo, GetMeIn and Seatwave.
According to the Fanfair Alliance the estimated value of the UK secondary ticketing market is worth $1.4 billion per annum.
On its website, StubHub describes itself as having "reinvented" the ticket marketplace in 2000.
"Every order is 100% guaranteed, with customer service all the way to your seat. We back every order so you can buy and sell tickets with 100% confidence. Trusted by fans worldwide, StubHub lets you buy and sell tickets safely and easily," the website says.
The annual Six Nations championship, which sees England, Wales, Ireland, Scotland, Italy and France face each other over a two-month period, consistently attracts big crowds across Europe.
A recent report judged it the best-attended sports event in the world with an average crowd of 72,000 across its 15 games in 2015 -- more than the NFL and the 2014 FIFA World Cup.
Both England and Wales head into this weekend's highly anticipated clash off the back of emphatic victories.
While many expected Wales's encounter with Scotland to be a tight affair, the home side put in a dominant display in Cardiff.
Tries from Leigh Halfpenny, Gareth Davies and Steff Evans condemned Gregor Townsend's men, expected to enjoy their best tournament in recent memory, to a 34-7 defeat.
England was equally ruthless in Rome as wing Anthony Watson and No. 8 Sam Simmonds both grabbed a brace of tries each to help their side to a 15-46 victory over Italy.
It was Australian Eddie Jones' 23rd victory from 24 games in charge as his side goes in pursuit of an unprecedented third-straight Six Nations title.
Wales has named an unchanged starting line-up for Saturday's game with Lions winger George North coming onto the bench.
Games between England and Wales tend not to disappoint. The last 10 times the sides have met, half have been decided by five points or fewer.
England has won the past three, the most recent an enthralling encounter settled by a late Elliot Daly try in last year's Six Nations.