British Prime Minister Theresa May wanted to alert her husband after Trump held her hand 'by surprise' during a 2017 visit

• During a 2017 US visit, Trump and May were pictured holding hands outside The White House.
• The hand-holding took May 'by surprise,' her former chief of staff has revealed in a documentary.
• May tried to alert her husband before the pictures hit the media, The Guardian reported.

Former British Prime Minister Theresa May was alarmed by former President Donald Trump's decision to hold her hand during a 2017 visit to the White House, according to a documentary seen by The Guardian.

"He held her hand going through the colonnades, which took us all by surprise, and as it turns out, took Theresa by surprise," Fiona Hill, the former Downing Street joint chief of staff, said in the documentary.

"She couldn't really take her hand back, so she was stuck," Hill continued.

"The first thing she said [afterward] was 'I need to call Philip just to let him know that I've been holding hands with another man before it hits the media,'" she added.

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The hand-holding took place during May's two-day visit to the US, marking Trump's first meeting with a foreign leader after his 2017 inauguration.

Also, during this visit, May reportedly witnessed a "toe-curling" outburst from Trump.

In the BBC's three-part documentary series, "Trump Takes on the World," Hill recalled the former president berating his advisers.

After Trump was informed that Putin had called The White House but not been through, it took place, reported The Guardian.

"Trump, at this point, looks not orange but red. He flipped. Furious," Hill said in the documentary.

May and Trump famously had a fractious working relationship. The former president was reportedly so dominant in calls with May that she only had 5 seconds to make her point.

Trump would often scold her in phone calls, according to CNN.

The former president called her "a fool," the media outlet reported.

The pair publicly clashed in November 2017 when May criticized Trump for retweeting anti-Muslim videos by far-right group Britain First.

In a tweet, Trump responded: "Don't focus on me, focus on the destructive Radical Islamic Terrorism that is taking place within the United Kingdom."