ISLAMABAD - PPP Chairman Bilawal Bhutto Zardari was due to embark on an eight-day visit to the US on Sunday on the invitation of the local Pakistani diaspora. During his visit, the PPP Chairman will also visit New York and Washington, meet American legislators, senior officials and media organisations. He will also address a number of think tanks. The visit of Bilawal  comes at a time when President Zardari is in Chicago to attend an important Nato summit on the future of Afghanistan.