In 1954, she sang Antonia in Offenbach's The Tales of Hoffmann before Queen Elizabeth II who was on her first tour of Australia.
[4] In order to gain greater skill, she moved to London to study under the tenor Joseph Hislop who had also coached Jussi Björling and Birgit Nilsson.
[1] After returning to Australia she quickly started to make a name for herself, taking soprano roles in operas by Mozart and Puccini, amongst others.
[4] In 1969 Fretwell sang opposite Tito Gobbi in Falstaff, finally joining the ensemble of The Australian Opera in 1970.
She did not want any fanfare or accolades at her last performance, and therefore only the management of the Australian Opera knew of her decision to retire in the late 1980s.
She simply gave her last performance, then quietly went to her dressing room, packed up her makeup and personal belongings, and went home to her beloved house at Bayview, on the northern beaches of Sydney, and reverted to her married name of Betty Simmons.