Madonna also began work on her thirteenth studio album, with collaborators including Avicii, Diplo and Natalia Kills. In December 2014, thirteen demos recorded for the album leaked onto the Internet. She posted in response that half of the tracks would not be used on the final release, while the other half had "changed and evolved". The album, titled Rebel Heart, was released on March 10, 2015. From September 2015, she embarked on the Rebel Heart Tour to promote the album; the tour ended in March 2016 and traveled throughout North America, Europe and Asia and was the singer's first visit to Australia in 23 years, where she also performed a one-off show for her fans. It grossed a total of $169.8 million from the 82 shows, with over 1.045 million ticket sales. While on tour Madonna became embroiled in a legal battle with Ritchie, over the custody of her son Rocco. The dispute started when Rocco decided to continue living at England with Ritchie when the Rebel Heart Tour had visited there, while Madonna wanted him to return with her. Court hearings took place in both New York and London, and after multiple deliberations, Madonna decided to withdraw her application for custody, and appealed for a mutual discussion between herself and Ritchie about Rocco.