warren buffett celebration
Berkshire Hathaway CEO Warren Buffett is seen on a cellphone camera as he talks to reporters prior to the Berkshire annual meeting in Omaha, Nebraska, May 2, 2015. Reuters

Warren Buffett told CNBC on Thursday the United States economy will perform well under President Donald Trump. The chairman and CEO of Berkshire Hathaway said: "America works, I've said this before. It'll work wonderfully under Hillary Clinton, and I think it'll work fine under Donald Trump."

Adding that the U.S. has a "secret sauce," the billionaire investor and philanthropist said: "It doesn't work all the time perfectly, but you just look at where we go, milestone after milestone. Never bet against America."

Buffett was speaking at an event Thursday night in New York for a new HBO documentary about his life, "Becoming Warren Buffett," that debuts Jan. 30.

In the presidential election, Buffett supported Clinton, even organizing fundraisers for the Democratic candidate. But after Trump won the election, Buffett told Fortune in an interview in November that Trump won't ruin the economy or the stock market. He also said he was still buying the same stocks he was before Election Day on Nov. 8, and that the election did not make him pessimistic about the U.S. stock market.

Buffett also mentioned being unsure about what will happen to the stock market in ten days or in the coming years. However, he said: "It's going to be higher 10 years, 20 years from now. There will be hiccups from time to time in the economy."