In 1999 Maia Estianty and her husband Ahmad Dhani established a musical duo consisting of a singer and musician, based on concepts pioneered by international bands such as Roxette and Savage Garden.They began looking for a singer. Mambo convinced Dhani to hire her by calling "at all hours of the day"[a] after meeting him while at a café in Pondok Indah Mall in South Jakarta; she had chosen to seek out Dhani because of his previous experience with new singers, including Reza Artamevi, and had heard that he frequented the mall. After her sixth audition for the band, named Ratu, meaning Queen, she was chosen to be its vocalist. Although Mambo begun studying economics at Trisakti University, owing to the pressures of her contract she dropped out. 　　After three years of training, during which time Mambo joined Dhani's band Dewa 19 as a backing singer, Ratu released its first album, Bersama (Together), in 2003. It had a rhythm and blues (R&B) flavour and featured Mambo on vocals and Estianty on instruments. The album was a commercial success, selling 250,000 copies. With her portion of the proceeds, Mambo paid for both of her brothers to attend university and bought a car. Although Mambo and Estianty began work on another album, Mambo withdrew from the group in 2004 after widespread reports that she was pregnant and unmarried; Mambo said that she had been fired by Estianty, although she admitted that her pregnancy had been a factor.She was officially replaced on 7 April 2005 by Mulan Jameela, a café singer from Bandung who took the stage name Mulan Kwok.