Tom Cruise tonight urged his fellow countrymen to get behind new President Barack Obama.
Speaking at the premiere of his new film Valkyrie, Cruise said Mr Obama had brought a sense of hope to the nation, but faced challenges which needed the whole country's support.
The actor will be hoping the movie is received better here than it was in Germany.
Valkyrie tells the true story of Count Claus Von Stauffenberg's attempt to assassinate Hitler with a briefcase bomb towards the end of the Second World War.
Descendants of the Prussian aristocrat have criticised Cruise's performance as "stiff" and lacking in charisma.
The reviews did not put off a hardy band of Cruise enthusiasts, who braved the chilly weather to attend the premiere in London's Leicester Square.
Among the crowd were a small group of anti-Scientology protestors wearing masks and waving banners.
Cruise said he was delighted to be back in London for the premiere despite the cold.
Asked what Obama's election had brought to the US, Cruise replied: "Hope - absolute hope.
"He has a challenge ahead and it's up to us as a country, it's not just up to him.
"We have got to support him and I believe he is going to do it."
The Hollywood star arrived with wife Katie Holmes, who wore a shimmering blue dress.
After ushering her into the cinema, Cruise spent nearly an hour signing autographs and posing for photos with fans.
He is making the most of his trip to the UK, appearing on Jonathan Ross's first Friday night BBC1 chat show since Ross's three-month suspension for prank calls he and Russell Brand made to Andrew Sachs.
Cruise said he had heard about the scandal but said he thought it was time to move on from it.
Eddie Izzard, who starred alongside Cruise in Valkyrie insisted the American's reputation as a strict Scientologist was not an issue during filming.
Izzard said: "I'm not sure exactly what the Scientologist thing is. Lots of people have different faiths. I personally don't believe in any organised Gods because I don't see any organisation in the way the world has progressed.
"I always think if there is a God he would have flicked Hitler's head off. He would have thought hang on, this guy is going to take everyone out, I'll flick his head off."
Bill Nighy, who played another conspirator in the film, also said Cruise's religion did not feature during the shoot.
Nighy said: "He was wonderful to work with, exemplary.
"(His religion) was not a feature of the working experience. He was a dreamy guy to do business with, he was inspirational and courteous and generous to everyone around him."
Valkyrie opens in cinemas on Friday.