<P> In 2007, Sia released a live album entitled Lady Croissant, which included eight live songs from her April 2006 performance at the Bowery Ballroom in New York and one new studio recording--"Pictures". A year later, she left Zero 7 on friendly terms, replaced by Eska Mtungwazi as the band's frontwoman . Sia released her fourth studio album, Some People Have Real Problems on 8 January 2008 . The album peaked at No. 41 in Australia and was certified gold by the Australian Recording Industry Association . It charted at No. 26 on the US Billboard 200, becoming Sia's first album to chart in the United States . </P> <P> Some People Have Real Problems yielded four singles . The lead single, "Day Too Soon", was released in November 2007 and peaked at No. 24 on the US Hot Dance Club Songs . The second single, "The Girl You Lost to Cocaine", was made available in March 2008 . The single peaked at No. 11 in the Netherlands and No. 12 in Spain; it additionally reached No. 8 on the US Hot Dance Club Songs . The third single from the album, "Soon We'll Be Found", was made available in October 2008 . The Bart Hendrix Deep Dope remix of "Buttons" was issued as the final single from Some People Have Real Problems in February 2009 . </P> <P> In May 2009, Sia released TV Is My Parent on DVD, which includes a live concert at New York's Hiro Ballroom, four music videos and behind - the - scene footage . At the ARIA Music Awards of 2009, Sia won the Best Music DVD category for TV Is My Parent . She also received a nomination for Best Breakthrough Artist Album for Some People Have Real Problems . </P> <P> In 2009, American singer Christina Aguilera approached Sia about writing ballads for Aguilera's then - upcoming sixth studio album . The final product, Bionic, includes three songs co-written by Sia . Later in 2010, Sia also co-wrote "Bound to You" for the soundtrack of the American film Burlesque, which starred Aguilera and American singer Cher . The song was nominated for Best Original Song at the 68th Golden Globe Awards . In May 2011, Sia appeared on the inaugural season of the U.S. version of The Voice as an adviser for Aguilera, who served as a vocal coach and judge . </P>

Who is considered to be the first true pop star