The relationship between George Bush and Tony Blair will not change despite the PM's announcement he will step down, the White House has said.
Mr Bush and Mr Blair have enjoyed a close relationship for five years
The US president's spokesman Tony Snow insisted Mr Blair was "a valuable ally" and said the pair still had "a lot of work to do" on the world stage.
"He is somebody whose counsel the president much values," Mr Snow added.
When they met in May, Mr Bush said he wanted Mr Blair to remain PM until the end of his presidency in 2009.
"He's still the prime minister of Great Britain, he's a valuable ally," Mr Snow told reporters.
"He is somebody whose counsel the president much values and whose co-operation the president depends upon.
"And at this point we're not sitting around writing encomia for Tony Blair. We're instead busy working with him."
Meanwhile, Irish Prime Minister Bertie Ahern has also offered his strong support for Mr Blair.
The taoiseach praised Mr Blair as a "great leader and a great colleague to work with" on EU and Irish issues.
Mr Ahern said he hoped Mr Blair stayed in office as the talks deadline for power-sharing between Northern Ireland's political parties looms.