The Prime Minister beamed as she clearly enjoyed rubbing shoulders with media-savvy French President Emmanuel Macron in the age of Instagram and Twitter.
The two heads of government packed a host of excited diplomats into the photo - dubbed "le selfie" - for an upbeat end to the UK-France summit.
Mr Macron held the phone aloft and snapped Thursday night's photo at a reception of young leaders of the Franco-British council, held at the Victoria and Albert Museum in London.
But it was the UK leader who got to post it to her own Twitter account, proclaiming that she was "proud to celebrate the extraordinary values and the talented people who link our countries".
Mrs May is keen to burnish Britain's credentials as a big player on the world stage, but also her and her party's own image on social media.
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But she is only the latest in a line of politicians to jump on the selfie bandwagon.
Her predecessor David Cameron, former prime minister of Denmark Helle Thorning-Schmidt and US President Barack Obama once took a much-criticised selfie at the memorial service for Nelson Mandela.
Mr Obama snapped another one up with his vice-president Joe Biden.
While ex-White House hopeful Hillary Clinton had a selfie taken with Kim Kardashian.
But who could forget Ed Miliband, former leader of the Labour party?
The Doncaster North MP did manage to approach going "viral" for photobombing a group of girls on the London underground.
And he even posed for one with The Only Way Is Essex Star, Joey Essex, an unlikely attendee at a Labour rally in Warrington in 2015.