The organisation confirmed the news in a comment on Attenborough's post, writing: "Congratulations Sir David - a new record for the fastest time to reach one million followers on Instagram".
As his first post, Attenborough explained his decision to join Instagram in a video Thursday morning.
They detail in the caption that the account will post exclusive messages from the broadcaster recorded exclusively for the platform, as well as behind the scenes footage from the upcoming Netflix series.
As per Guinness World Records, the followers on his account shot up to one million-mark within four hours of him posting the video.
He now has 2.5 million followers.
The film addresses some of the biggest challenges facing life on our planet, providing a snapshot of global nature loss in a single lifetime.
On his account, a video was shared a video with fans that aimed to inspire a change.
Colin Butfield, WWF's Executive Producer for David Attenborough: A Life On Our Planet, said: "We can not ignore the warning signs from nature any longer".
To a degree, but in the case of 94-year-old Sir David Attenborough, he's put even the most well-known of influencers to shame.
The documentary maker has enlisted his younger colleagues to help him join the social media site.
"Social media isn't David's usual habitat so while he's recorded messages exclusively for Instagram, like the one in this post, we're helping to run this account", explained account runners Collin Butfield and Johnnie Hughes.