Ratu was an Indonesian music duo formed in 1999 with Maia Estianty, then the wife of musician Ahmad Dhani, on instruments and Pinkan Mambo on vocals.

After a short break caused by Mambo's departure in 2004, the group formed anew with Mulan Kwok as vocalist.

Satu (Number One; 2006), sold 200,000 copies on the day of its release, a record for an album by an Indonesian female group.

In a later interview, she explained her motivations: "I wasn't following on the success of Krisdayanti dan Anang, a husband and wife who had made an album together.

"[b][2] With Dhani's guidance, in 1999 Maia decided to form a duo consisting of a singer and a musician, with the name Ratu.

[3] After three years of preparation, in January 2003 Ratu launched their debut album Bersama with Sony Music Indonesia.

Other musicians involved on the album included Bintang (bass), Denny Chasmala, Andra Ramadhan and Taras (guitar), Agil Cinere (drums), Donni (flute), Sa'unine (strings) and Henry Lamiri (violin).

[9] However, on 14 October 2004 Mambo announced she was leaving the group amidst widespread media coverage of her being pregnant outside of wedlock.

[16] While looking for a new vocalist, Maia met Mulan Kwok, a performer at Barbados Cafe in Bilangan Kemang, Jakarta, in December 2004.

[20] "Teman Tapi Mesra" was an overnight hit in Indonesia, Malaysia, and Singapore and enjoyed by both adults and children alike.

The term "Teman Tapi Mesra", often abbreviated TTM, became widely used to describe those in a physical relationship without an emotional one.

[28] Maia acted in Extravaganza, a comedy show on Trans TV, while Mulan starred in several television films.

[31] Noting the role that infotainment media had played in the band's success, Maia said "Ratu should give thanks to all those reporters who gave us fame with their gossip.

At the tenth Anugerah Musik Indonesia, the band received three nominations and won Best Produced Work for "Teman Tapi Mesra".

[8] At the end of 2006, Ahmad Dhani threatened to disband the group if Maia did not cut back on her performance schedule; he felt she was too busy, to the point of forgetting their children.

[38] He then fired the group's manager, Vita Ramona, who threatened to bring Dhani to court if he did not apologize for perceived defamation.

[39] This situation was exacerbated when Mulan publicly complained of not receiving her share of the band's money and a lack of transparency in the management.

She participated in the concert tour A Mild Live Soundrenaline with Shanty, Bunga Citra Lestari, and Ghea—a winner of Indonesian Idol.

[45] Mambo, the Ratu's original vocalist, had already released a solo album, entitled Aku Tahu Rasanya (I Know How It Feels) in 2006.

[46] In 2009, "Teman Tapi Mesra" was bought by LadyLike, a Swedish girl band, and released in the European market as the English-language "Dreaming of the Time".