A rare portrait of Elizabeth Taylor by Andy Warhol is expected to be the top lot at Christie's auction of post-war and contemporary art on June 30 in London.

"Silver Liz," dated 1963 and unseen in public for more than 20 years, is estimated to be worth 6-8 million pounds ($9-12 million), and two auctions that make up the series are expected to fetch 54-77 million pounds in total.

Last year, three series of post-war and contemporary sales held in February, June and October raised 55 million pounds, underlining the strength of the recovery in fine art prices in recent months that has seen world auction records tumble.

Among the other highlights are "Mappa" by Alighiero Boetti, a map of the world woven by women from an Afghan village, underlining the theme of globalization. It is estimated to sell for 0.9-1.2 million pounds.

Christie's will also offer eight works by the so-called "YBAs" (Young British Artists), including three which were exhibited at Charles Saatchi's 1997 show "Sensation," which helped launched the careers of Damien Hirst, Tracey Emin, the Chapman Brothers and Glenn Brown.

Auction favorites Jeff Koons, Gerhard Richter, Jean-Michel Basquiat and Andreas Gursky will also be represented at the sale.