Prince William was joined by the Duchess of Edinburgh for a rare joint appointment as they attended a screening at the renovated Battersea Power Station.
The heir to the throne attended the event with Sophie in south west London on Tuesday night.
On the agenda for the night was a screening of the documentary Rhino Man, which was produced by charity Global Conservation Corps and tells the story of heroic rangers protecting the endangered creatures from poachers.
The unlikely pair arrived together in a black 4x4 as the Princess of Wales and Duke of Edinburgh - William’s uncle - stayed at home.
Prince William’s official Twitter account said of the engagement: “This evening’s screening of Rhinoman provided a stark reminder of how wildlife rangers are putting their lives on the line every day in the critical fight to end wildlife crime.
“It is work United for Wildlife plays a crucial part in - disrupting this transnational organised crime and making it impossible for traffickers to transport, finance or profit from illegal wildlife products.”
The Prince and Princess of Wales sat with the Duke and Duchess of Edinburgh in the front row at King Charles’ coronation in Westminster Abbey.
An expert previously said The Princess of Wales and the Duchess of Edinburgh are a "force to be reckoned with" after becoming the "stars" of the Royal Family.
Despite their 17-year age gap, both Kate and Sophie have formed a sweet and fun bond and are often seen chatting and giggling at events.
And according to BBC royal correspondent Jennie Bond, Sophie and Kate are a "force to be reckoned with".
She told OK! : "It is so much more evident now that Catherine and Sophie are key members of the list of working royals. At a Buckingham Palace garden party, we saw them taking their place as senior members of the family.
Earlier this month The Duchess of Edinburgh was hailed as one of King Charles' "secret weapons" with a more prominent role set to be lined up for her.
Sophie has been given important and impactful visits in recent years on behalf of the monarchy, but they have gone under the radar due to publicity surrounding more high-profile members of the royal family.
It is thought she was particularly close to the late Queen Elizabeth II since joining the family in 1999 following her marriage to Prince Edward.
And it is believed that her influence has grown over the years and has seen her make historic trips, including a four-day secret visit to Iraq last month.
