Mickelson joined a field that included Ernie Els, two-time defending champion Adam Scott and current U.S. Open champion Angel Cabrera at what is billed as Asia's richest national Open at $4 million.
Scott will attempt to win his third straight title at the Nov. 1-4 tournament on the par-71 Serapong course on the resort island of Sentosa.
Also bidding for the title are Vijay Singh, former U.S. Open champion Michael Campbell, Ryder Cup star Darren Clarke and Shingo Katayama.
Barclays PLC took up the Asian Tour-sanctioned tournament's title sponsorship last year and the financial services company has pledged to increase the prize money to $5 million in 2008.
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