Stephen Moyer and Alexander Skarsgard are competing to raise the most money for their favourite charities with a series of online auctions.
Both actors have put personal items and memorabilia up for sale on eBay.com and the star with the smallest total at the end of the contest has agreed to be photographed wearing a t-shirt designed by the winner.
Moyer's 'modesty sock' - used to cover his genitals during filming of the vampire show - is proving popular with fans, with the highest bid currently standing at $545 (£363), while an autographed script has reached $900 (£600).
The Brit is backing the Gulf Aid organisation, while Skarsgard has picked the SOS Children's Villages charity, which aims to help orphaned kids in the Ukraine.
The pair have shot to fame in hit TV series True Blood and the show is currently in it's third season in the U.S.
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