Perhaps he was just trying to be helpful, given UK Prime Minister Boris Johnson isn't long in the job.

But the world's media were left speechless by a question put to them by US President Donald Trump at the G-7 summit in the French resort town of Biarritz.

"Do you know who this is?" Trump asked as he gestured towards Johnson during a photo opportunity before the two entered a private meeting.

"Does everybody know?"

All eyes are on the two leaders, who are expected to face intense pressure from G-7 attendees over Britain's plan for a Brexit deal and America's ongoing trade war with China.

Despite Trump's bizarre introduction of his British counterpart, he offered a ringing endorsement of Johnson, saying he's "the right man" to get Brexit done.

"He needs no advice. He is the right man for the job."

The two met on Sunday over breakfast to discuss a comprehensive trade agreement between Britain and the US.

In a joint statement released shortly after, the two said they would create a working group on trade issues.

That news comes amid reports that Johnson plans to tell European Union leaders the UK will leave without paying a £30 billion ($58 billion) Brexit "divorce bill" if they don't agree to changes.

Earlier, Trump suffered a rebuke before he even landed in Biarritz courtesy of European Council president Donald Tusk, who abruptly shot down his controversial push to readmit Russia to the exclusive Group of 7.

"Under no condition can we agree with this logic," Tusk said.

Russia was kicked out of what was then the G8 in 2014 after its annexation of Crimea from Ukraine.

"When Russia was invited to the G-7 for the first time, it was believed that it would pursue the path of liberal democracy, rule of law, and human rights," Tusk said.

"Is there anyone among us who can say with full conviction, not out of business calculation, that Russia is on that path?"

He said he would ask the G-7 to consider inviting Ukraine to next year's summit instead.

Trump floated the idea of restoring Russia's membership before last year's summit as well, and received a similarly hostile response.

He doubled down during a gaggle with reporters in the Oval Office on Tuesday.

"I think it's much more appropriate to have Russia in," Trump said.

"I could certainly see it being the G-8 again."

Trump's first bilateral meeting in Biarritz was with French President Emmanuel Macron, the host of this year's summit.

The pair spent four minutes in front of the cameras, sitting at a dining table — exactly the kind of awkward, cringe-worthy setting you expect at these events.

Macron sucked up three of those minutes talking about a range of policy issues including climate change, trade, North Korea and Iran.

In response, Trump highlighted his relationship with the French leader and complimented the weather.

"We actually have a lot in common, Emmanuel. We've been friends for a long time. Every once in a while we go at it a little bit, not very much, but we get along very well. We have a very good relationship," Trump said.

"We have some really great things to talk about. And we couldn't ask for better weather or a more beautiful location. But next year we'll be hosting in the United States so that'll be great. Very good. That'll be great. We'll do a good job.

"But so far so good. The weather is perfect, the guests are fantastic, everybody's getting along. We'll accomplish a lot this weekend."

The US President copped some criticism from the talking heads back home.

"When you saw the lunch, Macron laid out his agenda and Trump is talking about the weather," Princeton University Professor Eddie Glaude told MSNBC.

"He's completely out of his depth."

As host, Macron has officially decided the summit will focus on inequality, though more contentious issues like trade and climate change have already been broached.

Johnson, who is scheduled to meet with Trump on Sunday morning (French time), has indicated he will urge the US President to scale down his trade war with China.

"I am very worried about the way it's going. The growth of protectionism, of tariffs that we're seeing," Johnson said.

"This is not the way to proceed. Apart from everything else, those who support the tariffs are at risk of incurring the blame for the downturn in the global economy, irrespective of whether or not that is true.

"I want to see an opening up of global trade. I want to see a dialling down of tensions, and I want to see tariffs come off."

The trade war escalated again late this week, with both the United States and China announcing tens of billions of dollars worth of new tariffs.

Before leaving for the G-7 summit, Trump also threatened to impose tariffs on French wines in retaliation to France imposing a sales tax on American tech giants Google, Facebook and Apple.

Tusk then warned that if the US were to impose new tariffs, the European Union would respond with its own.

Johnson is under his own form of pressure as he pushes for changes to the Brexit deal the European Union negotiated with his predecessor, Theresa May.

Tusk took aim at Johnson as well, warning him he could "go down in history as Mr No Deal" and pointing out he was "the third British Conservative prime minister with whom I will discuss Brexit".

"The EU was always open to co-operation when David Cameron wanted to avoid Brexit, when Theresa May wanted to avoid a no-deal Brexit and we will also be ready now to hold serious talks with Prime Minister Johnson," said Tusk.

"One thing I will not co-operate on is no deal."

In addition to the G-7 countries — France, Germany, Canada, Italy, Japan, the UK and the US — a number of guests have been invited. Those nations are Australia, Burkina Faso, Chile, Egypt, India, Senegal, Rwanda and South Africa.