Donald Trump is expected to ignore billionaire businessman Elon Musk's advice to stick with the Paris Accord on climate change.
Musk - who serves on three White House economic advisory councils - says he will dump Trump if the President withdraws US support on the major climate change agreement.
"Don't know which way Paris will go, but I've done all I can to advise directly to POTUS, through others in WH & via councils, that we remain," Musk said on Twitter.
He added he would have "no choice" but to depart Trump's advisory councils if the US pulled out of the climate deal.
Trump has tweeted that he will announce his decision on the Paris deal on Thursday 3pm (US time).
Musk, the billionaire business magnate CEO of electric carmaker Tesla and aerospace company SpaceX, is on Trump's manufacturing jobs council, his strategic and policy forum and his infrastructure council.
He has previously had to defend his position advising the President, telling critics they should want his voice on those councils offering views different to those of Trump's other advisers.
He has also had backlash against his business form anti-Trump customers because of his involvement with the White House.
Meanwhile, Trump has declared that abandoning the Paris climate agreement would be a victory for the American economy.
Many economists have big doubts.
They say the agreement would likely help create about as many jobs in renewable energy as it might cost in polluting industries.
Should the United States pull out of the pact and seek to protect old-school jobs in coal and oil, it would risk losing the chance to lead the world in developing environmentally friendly technology - and generate the jobs that come with it.
Under the Paris Accord, nearly 200 nations agreed in 2015 to voluntarily cut greenhouse gas emissions in a landmark agreement to fight climate change.
The pact became one of President Barack Obama's signature achievements.
But Trump campaigned on a promise to nix the deal, saying it would mean stricter environmental policies that would hobble the economy and cost jobs.