Kim Kardashian's 20-carat engagement ring from Kris Humphries sells at auction for $749k

Kim Kardashian's 20-carat engagement ring has sold at auction for a cool $749,000.

The enormous diamond ring, given to the reality star by ex-husband Kris Humphries, was purchased by an as-yet unknown buyer at Christie's in New York City on Tuesday.

Bidding for the 16.21 carat Lorraine Schwartz diamond began at $200,000 at the auction, entitled 'Bright and Beautiful'.

The ring, which features two 1.8 carat side diamonds, will end up costing the buyer $749,000 taking into account the auction house's mark-up.

'As the finale of the morning session, Lot 194 saw active participation in the room, on the phone banks, and from Christie's LIVE,' the auction house spokesman Gabriel Ford told MailOnline.

'This impressive diamond ring was sought out by 2 bidders in the back of the room, one online bidder and was ultimately won by a bidder on the phone.'

It was confirmed last month that Kris was selling the ring which was originally reported to have cost $2 million.

But following the estimate of Christie's jewellery experts, it appears that he paid far less for the ring than reported at the time.

But bad publicity surrounding the Humphries-Kardashian divorce may have had an effect on the sale.

Kris proposed to Kim with the ring back in May 2011 and it seems she returned the piece of jewellery to him after their marriage ended.

The Keeping Up With The Kardashians star was married to Kris for just 72 days before she filed for divorce at the end of October 2011.

Kim is now mother to baby North with her new beau - rapper Kanye West.