The British singer was spotted walking down Whitehall Lane in the middle of London. She was dressed casually and carried a blue horn.
Cameron is under fire after the recently released Panama Papers revealed that he owned shares in his late father's offshore fund, Blairmore Holdings, Time reports. Although offshore accounts are typically used in order to avoid paying taxes on large amounts of money, Cameron has claimed that he sold his shares in the offshore account once he became prime minister in 2010. (The prime minister is not specifically identified in the Panama Papers and he has never been charged with any crime relating to offshore funds.)
The revelations of the Panama Papers have already forced Iceland's Prime Minister Sigmundur David Gunnlaugsson to take a temporary leave of absence, according to the New York Times. Cameron's critics are pushing for him to follow suit.
The Panama Papers, a collection of millions of leaked from the Mossack Fonseca law firm in Panama, were released last weekend and have been called one of the biggest data leaks in history. The papers have named several international politicians as benefiting from the offshore accounts, including Gunnlaugsson, King Salman of Saudi Arabia and President Mauricio Macri of Argentina. The papers also named close associates of President Vladimir Putin of Russia and and relatives of President Xi Jinping of China, in addition to Cameron's father.
On Saturday, The Guardian reported that Cameron admitted he "could have handled" the Panama Papers news better, adding, "I know there are lessons to learn and I will learn them." The prime minister also added that he loved his father and was "very angry" about what some of the protesters and critics were saying about him in the wake of the Panama Papers revelations.