Millions follow Sir David Attenborough on Instagram after just one post

With just a single post, Sir David Attenborough has amassed more than 2 million followers on Instagram.

The 94-year-old's joined the photo-sharing social media site to spread a message of doom and gloom to Gen Z.

"Hello, my name is David Attenborough and I've been appearing on radio and television for the past 60 years but this is my first time on Instagram," the veteran natural historian explains in a video uploaded on Thursday night (NZ time). 

"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."

It's been just 14 hours since the Planet Earth host uploaded the clip, and he's already got 2.2 million followers. 

Helping him out are filmmakers Colin Butfield and Jonnie Hughes, who worked with Sir David on his new documentary A Life On Our Planet.

"Social media isn't David's usual habitat," they explained, using a word that will be familiar to longtime fans of the British national treasure. 

"As well as sharing the messages he's recorded especially for this account we'll also post some exclusive clips and behind the scenes content."

Sir David said despite the dire state of the planet he's documented since the days of King George VI, there is hope.

"We know what to do about it, that's why I'm tackling this new way - for me - of communication. Over the next few weeks I'll be recording messages to explain what the problems are and how we can deal with them. Join me or, as we used to say in those early days of radio, stay tuned."

Despite his fast start, he has a long way to go to catch up to stars like footballer Cristiano Ronaldo and pop singer Ariana Grande, who each have more than 200 million followers.