The production uses advanced equipment including remote underwater cameras, drones, and manned submersibles to capture newly discovered animal behaviours.

Viewers are taken into some of the world’s least understood marine environments, ranging from coral reefs and tropical islands to the darkest depths of the ocean.

In the newly released extended trailer, Attenborough promised to “venture even further” than ever before, describing the ocean as “an endlessly fascinating place”.

“We will uncover life that is more surprising, more intelligent, and even more precious than we ever realised,” he said.

“We will discover the extraordinary relationship we have with the ocean. One that has never been more important to understand.”

Sir David said he was “proud and delighted” to be associated with the project.