Sir David Attenborough has set a new Instagram record by becoming the fastest user in history to reach one million followers since Friends actress Jennifer Aniston.

The 94-year-old joined the social media site on Thursday and posted a video explaining his reasons for moving onto the platform.

Alongside the clip, the caption read: "Hello, my name is David Attenborough and I have been appearing on radio and television for the past 60 years but this is my first time on Instagram.

"And I’m making this move and exploring this new way of communication, to me, because as we all know the world is in trouble. Continents are on fire, glaciers are melting, coral reefs are dying, fish are disappearing from our oceans. The list goes on and on.

"But we know what to do about it and that’s why I am tackling this new way, for me, of communication. Over the next few weeks I will be recording messages to explain what the problems are and how we can deal with them. Join me, or as we said in the early days of radio, stay tuned."

In just over four hours, Sir David had reached the one million milestone, toppling the previous record of five hours and 16 minutes set by Hollywood actress and Friends star Jennifer Aniston.

At the time of writing, he had reached 2.8m followers.

And on Friday, the broadcaster and natural historian released his second video to Instagram looking back at the Apollo mission more than 50 years ago.

"Apollo mission: The earth is finite," the caption read.

"Over half a century ago, man went to the moon. David was watching from a television studio at the time and was fascinated at seeing our world from space for the very first time. These pictures changed the mindset of many across the world: we realised that the earth is finite.

"A Life On Our Planet film is produced by @silverback_films and @wwf_uk."

Attenborough’s new documentary, titled A Life On Our Planet, will be released on Netflix on Monday, September 28 and will show the devastation of the world’s wildlife at different points of his career.