, a lifelong environmentalist, walked the 'blue carpet' at London's Royal Festival Hall before meeting the beloved natural history TV presenter Sir David Attenborough and his daughter Susan inside the Southbank venue tonight. , shows no signs of slowing down as he uses his latest film to deliver an urgent message about the importance of a healthy ocean.

The naturalist, who has filmed environmental documentaries from over 83 different countries, will show why ocean recovery is vital for stabilising the climate, securing a healthier future for the population, and how marine protection, if immediately implemented, can help to turn the tide of the damage. Charles has met Sir David several times before as his work as an ambassador for the natural world and his passion for the planet overlap with the King's own work to promote sustainability, and protect nature and the oceans.

The pair seemed delighted to see one another again as they spoke about the film and Sir David's upcoming birthday. They chatted animatedly as they had their photographs taken before heading into the auditorium to watch the film.

On February 19th 1970, His Majesty, as Prince of Wales, first marked the 'growing menace' of oil and plastic pollution in the sea, during a speech at the 'Countryside In 1970' conference.

Since then, the monarch has continued to champion the importance of the ocean.

In the film, Sir David describes the oceans as "the greatest asset against climate change" before adding a stark warning.

"Today, it is in such poor health I would find it hard not to lose hope were it not for the most remarkable discovery of all," he said. "If we save the sea, we save our world. After a lifetime of filming our planet, I'm sure nothing is more important."

On arrival, the King was greeted by Kristin Rechberger, Founder and CEO of Dynamic Planet - who have co-produced the film. On the 'blue carpet', Charles was then introduced to guests of the Premiere before moving into the auditorium to watch the film.One of the film's co-producers, Dynamic Planet, is launching a new global initiative, 'Revive Our Ocean', to turn inspiration from the documentary into action.

Tony Nowlan, who produced Ocean, described the film as Sir David's "most important story he has ever told". He also said it was "marvellous" that the King was attending the premiere tonight.

He said: "It is absolutely wonderful, it is really, really marvellous. The prince and the King have done incredible things for the environmental world and conservation and this is just an extension of that. Their presence here really speaks to how this should be such a big moment in time. It could be such a moment in history to try and change and help save the ocean."

Ocean with David Attenborough will be released in cinemas on May 8, to coincide with Sir David's 99th birthday. It will be available to stream on Disney+ from Sunday, June 8.