Gasteen was named an officer, the second-highest level in the 31-year-old Order. Others newly honored included actress Nicole Kidman, who was one of eight named a companion of the Order, its highest level.

Born in Brisbane, Gasteen debuted at the Lyric Opera of Queensland in 1985 and soon became a regular performer with the Australian Opera and Victorian State Opera (since merged into Opera Australia). She launched her international career when she won the 1991 Cardiff Singer of the World competition, and has since performed with the Berlin State Opera, Metropolitan Opera, and other major companies.

In 2004, she sang Br‹nnhilde in the State Opera of South Australia's much-anticipated Ring cycle; this season she sings the role in the Royal Opera's new Ring.

Her other roles include Elektra, Senta in The Flying Dutchman, Aida, and Tosca.