In March 2009, Cyrus released "The Climb" (2009) as a single from the soundtrack to the . It was met with a warm critical and commercial reaction, becoming a crossover hit in both pop and country music formats. The soundtrack, which features the single, went on to become Cyrus's fourth entry to top the "Billboard" 200; at age 16, she became the youngest artist in history to have four number-one albums on the chart. She released her fourth soundtrack as Hannah Montana in July 2009, which debuted at number two on the "Billboard" 200. Cyrus later launched her first fashion line, Miley Cyrus and Max Azria, through Walmart. It was promoted by the release of "Party in the U.S.A." (2009) and the EP "The Time of Our Lives" (2009). Cyrus said the record was "a transitioning album [...] really to introduce people to what I want my next record to sound like and with time I will be able to do that a little more". "Party in the U.S.A." went on to become one of Cyrus's most successful singles to date, and is considered to be one of her signature songs. She next embarked on her first world tour, the Wonder World Tour (2009), which was a critical and commercial success. On December 7, 2009, Cyrus performed for Queen Elizabeth II and other members of the British royal family at the Royal Variety Performance in Blackpool, Lancashire.