Former US president Bill Clinton and Oscar-winning film director James Cameron are among the big names attending an Oxford conference next month.
They are among the speakers at an Oxford University event looking at how the world can still provide enough food, energy and water for an ever-growing population.
Mr Clinton will deliver the closing address at the invitation-only Re/Source 2012 forum next month.
It takes place on on July 12 and 13 at the Examination Schools, in High Street, close to University College, where Mr Clinton was a Rhodes Scholar.
Mr Cameron will speak at a gala dinner at the Ashmolean Museum for people attending the conference.
His films Titanic and Avatar are the two highest-grossing films of all time, but he also is a celebrated deep sea explorer.
In March he reached the bottom of the Mariana Trench, the deepest part of the Pacific Ocean, in his Deepsea Challenger submersible.
Other high-profile figures due at the event include the wildlife broadcaster Sir David Attenborough, former Foreign Secretary David Miliband; broadcaster and author Jonathan Dimbleby; Oxford University Chancellor Lord Patten; and the Nobel Prize-winning economist Amartya Sen.
Sir David King, co-director of the event and former Chief Scientific Adviser to the Government said: “There’s no doubt that our current model of growth is unsustainable.
“The way in which business leaders respond to these issues will shape the competitive landscape over the next 20 years and beyond.”
Mr Clinton first arrived in Oxford in October 1968 to study politics, philosophy and economics.
He did not leave the university overburdened with qualifications, once joking: “I think my class of Rhodes scholars had the lowest percentage of people getting degrees of any class in recent history.”
Since then he has made a number of visits to the city. In 1994 he received an honorary degree at the Sheldonian Theatre.
He was back twice in 2001, firstly to open the £13m Rothermere American Institute, travelling with his daughter Chelsea, who later studied at Oxford University herself.
The same year he spoke at a fundraising dinner at Chislehampton Manor in aid of Oxford’s Douglas House hospice and visited its sister children’s hospice Helen House.