Victoria McCrae, Sydney's self-professed "royal tragic", is one of the most persistent women in the Commonwealth after attempting to steal a kiss from Prince Harry during her third proposal to the grandson of the monarch.

The 21-year-old from Sydney, who has reportedly asked for the prince's hand in marriage three times, reached in to steal a kiss from the most eligible bachelor in the world while he greeted about 500 fans on the steps of the Opera House on Thursday.

Captain Wales, dressed in his British Army combat fatigues and navy beret, granted Ms McRae an intimate audience by leaning in for a peck on the cheek.