The current bid for Warne's cap has now surpassed the final auction price of the baggy green of cricket legend Sir Donald Bradman which was sold for $425,000 in 2003.
In a gliterring career which spanned over two decades, Warne played 145 Tests for Australia, picking up 708 wickets - 2nd highest in the world after Sri Lanka's Muttiah Muralitharan (800).
The final selling price of the cap could yet go even higher as the bidding is set to close at 10 am (AEDT) on Friday. After the bidding ends, Warne is also slated to award an autographed certificate to the highest bidder.
Warne's cap has not just surpassed Bradman's in terms of the auction amount but also zoomed past a number of other famous cricket memorabilia in the sport's history - notably the bat used by Mahendra Singh Dhoni in the 2011 WC final.