US President Donald Trump and his Chinese counterpart, Xi Jinping, have delivered broad smiles ahead of their high-pressured summit talks.
The leaders of the world's two biggest economies were seen shaking hands at the president's Mar-a-Lago retreat in Palm Beach, Florida.
The pair then formally posed with their wives, Melania Trump and Peng Liyuan, on the steps before traditional sit-down shots inside.
The couples will dine together to begin an overnight summit that will include a working lunch on Friday where the tone could become far less cordial.
Mr Trump last week tweeted that the summit would be "a very difficult one", with North Korea's missile tests, Chinese tensions with Taiwan and trade issues on what could become a combative agenda.
Chinese president Xi Jinping has hinted he is willing to remain patient over the Hinkley nuclear project as he raised the prospect of a major free trade deal between the UK and China in private talks with Theresa May.
A Number 10 official said Mr Xi understood why the new Prime Minister felt the need to take a fresh look at agreements made by David Cameron's administration, which saw her surprisingly delay the Chinese-backed Hinkley Point plant.
Although the project was not mentioned in the talks after the G20 summit, the official said President Xi "recognised the new Government would need to take some time before reaching decisions on some agreements pushed by the last government".
"President Xi said that they had the patience to wait for a resolution on those issues," the official added. "He said that they wanted to look at how we could strengthen our trading and economic relationship and that China was open to a bilateral trade arrangement with the UK."
Mrs May said she was hoping to visit China next year as President Xi welcomed her commitment to continuing what she described as a "golden era" in relations with Beijing.
Downing Street said the 30-minute meeting was "warm" with Mr Xi even commending the UK on Team GB's second-placed finish above China in the Rio Olympics' medals table.
US Secretary of State John Kerry told Chinese President Xi Jinping that tensions on the Korean peninsula were one of the challenging issues he would be discussing with Xi.
Mr. President, this is obviously a critical time with some very challenging issues - issues on the Korean peninsula, the challenge of Iran and nuclear weapons, Syria and the Middle East, and economies around the world that are in need of a boost.
China's parliament formally elected heir-in-waiting Xi Jinping as the country's new president, succeeding Hu Jintao, putting the final seal of approval on a generational transition of power.
The largely rubber stamp National People's Congress chose Xi in a tightly scripted ceremony at the Great Hall of the People in Beijing.
Xi was appointed party and military chief - where real power lies - in November.
I extend my congratulations and best wishes to the new Politburo Standing Committee of the Communist Party of China. 2012 marks the 40th anniversary of diplomatic relations between our two countries.
There are many things we can and need to do together as countries of global influence, and permanent members of the UN Security Council.
I am committed to deepening our cooperation with China in the interests of shared prosperity and security and developing our shared understanding of each other’s values.
The UK wants China to prosper, and I believe we have much to offer to help it do so.
The question for this generation of China's leaders and therefore for us as well on economic issues, on security issues, on critical environmental issues is whether or not we can engage them in a global system that's based on rules not just the pursuit of self interest.
I think what matters is that he has been part of a leadership team that has seen China prosper from opening up and I think that will continue internationally and of course the balance that they have to strike is how much openness they allow domestically.
The message I take from this is that the economic revolution continues.
During his announcement as the new chief of the Chinese Communist Party Xi Jinping said:
"Our responsibility is to rally and lead the whole party and the Chinese people of all ethnic groups in continuing to liberate our way of thinking, carry on reform and opening, further unleash and develop the productive forces.
"Work hard to resolve the difficulties the people face in both work and life, and steadfastly take the road of prosperity for all."
"In the new environment, our party faces many severe challenges and there are many pressing problems within the party that need to be resolved, especially some party members and cadres being corrupt, taking bribes, being out of touch with the people, undue emphasis on formalities, and bureaucratism.
"These must be addressed with great efforts. The whole party must be vigilant against them."