Has Barack Obama dyed his hair black to hide his greying locks?

Has Barack Obama dyed his hair black to hide his greying locks? - It's being seen as the most important visit by a Chinese leader in 30 years and, with all the world's eyes on him, who can blame Barack Obama for wanting to look his best.

For it appears that he has dyed his greying hair jet-black - giving him a new more youthful look.

Observers have said the 49-year-old U.S. President's hair has changed colour dramatically because of the pressures of the job since he assumed office two years ago.

On top of that, the four-day visit by Chinese President Hu Jintao is of particular importance for Obama as the world's superpower comes to terms with the Far Eastern country's growing influence on the world stage. By 2020 it is expected to overtake the U.S. as the world's largest economy.

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Turnaround: Jet black locks one week later

Something to tell us? The U.S. President had noticeably darker hair yesterday (right) than he did a week ago

The first picture was taken outside the Andrews Air Force Base, just outside Washington DC, as the President prepared to board Air Force One a week ago.

Seven days later as he spoke at a state dinner for Hu Jintao in the White House, his hair was apparently significantly darker.

China is also pressing the U.S. on a number of military fronts which is raising concerns within the States and abroad thereby increasing the pressure on Obama and the White House as it walks this political tightrope.

The visit is being ranked in importance by analysts to the one in 1985 when the then Chinese President Li Xiannian made a state visit.

It was the first by a Chinese head of state since the founding of the People's Republic of China in 1949. During the visit the two states signed a document agreeing to the peaceful use of nuclear energy.

But if Obama is feeling under pressure, there was better news for him today as it emerged his approval rating has surged to 53 per cent.

Just a month ago he was languishing eight points lower - and the rating is the highest since July 2009, according to the NBC/Wall Street Journal poll.

Fiery relationship: Michelle Obama smiles in a brilliant red-orange Alexander McQueen gown as her husband shakes hands with Chinese President Hu Jintao at a White House state dinner last night