We are now writing to ask you to confirm that you will make tackling the climate emergency a top priority.
Ellie Goulding is one of several celebrities who have called on Boris Johnson to make tackling the world's climate emergency a "top priority".
Actor James Norton, wildlife presenter Steve Backshall and former Blue Peter presenter Konnie Huq are also among the 12 stars who have written a letter urging the new Prime Minister to cut climate emissions to "net zero".
The letter asks Mr Johnson to prioritise help for people to switch to electric cars, as well as plant more trees and make homes more climate-friendly with cleaner heating systems.
It warns: "There is no greater risk to life on earth than climate change. Taking ambitious action to end our contribution to climate change is essential to protect all species and the ecosystems that we all depend upon for survival.
"As Prime Minister, we are now writing to ask you to confirm that you will make tackling the climate emergency a top priority, and commit to ramping up the policies and investment needed to get us on track to net zero."
The letter follows the decision by Theresa May's Government to set in law a new target for the UK of reaching net zero greenhouse gas emissions by 2050.
This means that emissions from cars, planes, buildings and farms must be urgently reduced and must not exceed the amount that could be removed from the air through measures such as tree-planting.
During the race to become Conservative Party leader, Mr Johnson tweeted that he would back a net zero target and make the UK a "global decarbonisation leader".
The letter says Mr Johnson should now "commit to a 10-year economic programme" which would decarbonise homes, ban the sale of fossil fuel cars by 2030, triple the amount of electricity from solar and wind power and increase forest areas in the UK to soak up carbon emissions.
The celebrities who signed the letter are supporters of organisations which make up The Climate Coalition, a collection of more than 130 groups representing more than 15 million people across the UK.
Coalition members include aid agencies Cafod, Christian Aid and Islamic Relief, community groups such as the Women's Institute and conservation bodies WWF, the National Trust and the Woodland Trust.
The latest move comes after more than 12,000 people travelled to Westminster last month to urge MPs to support measures that will end the UK's contribution to climate change.
The Climate Coalition's campaigns director Clara Goldsmith said: "Boris Johnson said that he would act on the climate crisis while he was campaigning to become Prime Minister. Now that he's in Downing Street, he's in a position to do so.
"The thousands of people - young and old - who have spoken to MPs in recent months about the need for action have made clear that the public support is there."
The other celebrities who have signed the letter are Charles Dance, Iwan Rheon, Cel Spellman, Jack Savoretti, KT Tunstall, Lucy Siegle, Stuart Rideout and Rankin.
A spokesman for the Department for Business, Energy & Industrial Strategy (BEIS) said: "We are leading the world in tackling climate change, going further and faster by becoming the first major economy to pass new laws for net zero emissions by 2050.
"Already we have cut emissions faster than any G7 country, and we will continue to embrace the opportunity of clean growth for the UK - including through our important bid to host crucial international climate talks next year."
Julia Hunt is the PA entertainment correspondent.