Mr Johnson broke the news after a large number of resignations from Tory colleagues but has said he wants to stay on as a caretaker PM until a new leader is chosen in autumn.
It seems Mrs May has found a reason to celebrate, by letting her hair down at Henley Festival.
The event runs from July 6-10, with a whole host of acts performing on the Thames.
Mrs May attended the event with her husband, Philip May, whom she married in 1980.
Singer-songwriter Craig took to the stage to perform his hit Nothing Like This, with a video capturing Mrs May getting her boogie on in the packed crowd.
As the rest of the audience jumped and waved their arms in the air, the politician showed off some rather intriguing dance moves, bopping her head from side to side while shrugging her shoulders up and down and flapping her arms.
She seemed to blend in pretty well, as other concertgoers were totally focused on the stage, leaving Mrs May to shimmy about with a male friend by her side.
The former leader dressed smart in a red dress with a statement necklace, while her friend opted for a black suit and bow tie – a stark contrast to the blue bomber jacket and white jeans worn by Craig as he performed.
Mrs May was Prime Minister from July 2016 until July 2019, when she too remained on as caretaker PM after her resignation from Number 10 before the winner of the six-week leadership contest was announced, at which point Johnson became her successor.
While she has been the MP for Maidenhead in Berkshire since 1997, there is speculation that she might return to her role as PM following Johnson’s exit – and technically, she could.
However, it seems unlikely given her flippant response to the matter.
She didn’t rule it out when quizzed on the events but laughed at the idea of stepping in.
‘From everything I hear, I don’t think there’s going to be a caretaker Prime Minister in the sense of somebody else coming in,’ she said after delivering a speech at the Institute for Government.
Delivering his resignation speech while standing outside Downing Street, Mr Johnson admitted that it was ‘painful’ to be leaving office, but stated: ‘Them’s the breaks’.
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