Tony Blair will hold his last official foreign talks today plus his final press conference as Prime Minister when he welcomes ex-film star Arnold Schwarzenegger, the governor of California, to Downing Street.

The breakfast meeting with the "Governator" at No 10, primarily on climate change, is expected to come just hours before Mr Blair's appointment as a special envoy to the Middle East is confirmed by a meeting of representatives from the Quartet - the UN, US, EU and Russia - in Jerusalem. Yesterday, when the Prime Minister's spokesman was asked about Mr Blair's appointment, he refused to deny it, saying only: "Let's not get ahead of ourselves."

One source close to the Quartet said: "Blair's appointment has been 150% approved. The Jerusalem meeting is all about arranging the logistics, making final arrangements and getting the announcement out."

The prime mover behind the PM's appointment has been American President George W Bush with support from Ehud Olmert, the Israeli premier. Given Mr Blair's central role in the Iraq war, the prospect of his appointment has raised eyebrows in certain quarters, though it is thought Vladimir Putin, the Russian president, has decided not to object.

Javier Solana, the EU's high representative on foreign affairs, is believed to be unhappy at Mr Blair's appointment because it could distract from his own role in the region. However, diplomats have insisted the PM's new role will focus on Palestine and will not directly involve talks between the Palestinian Authority and the Israeli government.

This morning, Mr Blair will hold round table talks with Mr Schwarzenegger, star of Hollywood's Terminator films, alongside David Miliband, the Environment Secretary, and business leaders when they discuss global warming.

The talks will pick up from last August when the Prime Minister visited the governor in Los Angeles to agree on working together to reduce greenhouse gases and promote low carbon technologies. At the time a mission statement was issued saying the two would, among other things, "share experiences" and "find new solutions" on climate change.

Asked if what has already been dubbed Mr Blair's "hasta la vista" meeting would be the PM's last bilateral talks at No 10, his spokesman said: "I suppose that will be the case."