Sir David Attenborough has been replaced as the narrator on a special instalment of Planet Earth III on Monday. 

The hit BBC nature documentary series, which first premiere in 2006, has had a major shake-up for its latest episode.

To celebrate Earth Day, children have taken over the narration from the legendary broadcaster and naturalist Sir David, 97. 

Planet Earth III has collaborated with BBC Children In Need, who have selected schools that had helped its fundraising efforts to feature in the episode.

49 schoolchildren ranging from ages nine to 13 can be heard reading from Sir David's original scripts in the episode, which is now available on BBC iPlayer.  

The episode's synopsis reads: 'You don't have to be Sir David Attenborough to become a voice for nature.'

Introducing the episode, the children said: 'Welcome to a very special episode of Planet Earth III, narrated by schoolchildren from all over the UK.

'Because you don't have to be Sir David Attenborough to become a voice for nature.

'We can all speak up on behalf of our wonderful planet Earth. It's one of the most powerful ways to help protect it.'

As part of the Become A Voice For Nature campaign, schools across the UK played the special episode in a virtual assembly. 

Wildlife biologist and presenter Lizzie Daly, who is involved in the virtual assembly, said: 'I'm thrilled to be presenting the Become a Voice for Nature live schools assembly on Earth Day!

'I want to encourage schools across the UK to download a Become a Voice for Nature resource pack from the BBC Children in Need website and join us to hear more from the producers of Planet Earth III and learn more about the planet, how it impacts our lives and what we can do to protect it.

'I can't wait, to see you all there.'

Claire Hoyle, director of income, marketing and communications at BBC Children In Need, said: 'The Become A Voice For Nature campaign is about encouraging pupils from schools nationwide to come together on Earth Day to learn more about protecting our planet and how we impact it.

'We really wanted to be able to show our appreciation to schools who fundraise for BBC Children In Need each year, so we're delighted to be delivering this live assembly and we are so thrilled to see pupils voicing this special episode.

'A huge thank you to all of the pupils and schools for their continued support and fundraising efforts for BBC Children In Need.'

Sir David has won the hearts of the nation throughout his career, which has first started more than seven decades.

His nature documentaries have inspired people worldwide to take a more profound interest in the nature surrounding them, including plant and animal life.

The Planet Earth III: Narrated by Schoolchildren episode is available to watch on BBC iPlayer now and will air on BBC One on May 6.