Her Majesty stepped out overnight, alongside granddaughter-in-law Meghan Markle, in a vivid lime green coat dress and it has a special meaning.
The brightly coloured frock is believed to be a nod to the one-year anniversary of the Grenfell Tower fire tragedy that claimed as many lives as 80.
Green has become the official colour of the anniverary, with the shell of the London Tower, along with other prominent landmarks, lit up in the shade.
UK residents have also been encouraged to wear 'green for Grenfell' - and on social media, many are claiming Queen Elizabeth's lime-coloured outfit is no coincidence.
Throughout their visit in Cheshire, northwest of London, the Duchess of Sussex and her new grandmother-in-law, were clearly enjoying each other's company, enjoying laughs among the two of them.
While watching a performance by local schoolchildren, the pair were seen chatting excitedly and making whispered remarks to one another. Neither Meghan nor Her Majesty could suppress their laughter at certain moments.
The former actress and Her Majesty travelled to Chester aboard the Royal Train on Wednesday night, arriving at Runcorn Station on Thursday morning.
Meghan's invitation to travel on board with Queen Elizabeth II was a rare privilege that made royal history. No other young royals have ever travelled alongside the Queen on the train overnight for a royal engagement - including Kate Middleton, Prince William and Prince Harry.
Meghan opted to wear an beige caped dress by Givenchy, while the Queen stood out from the crowds in a vivid green coat.
They were accompanied by Samantha Cohen, the Australian-born royal adviser who was recently appointed Prince Harry and Meghan's private secretary.