Warren Buffett said Berkshire Hathaway Inc. has bought shares of internet retailing giant Amazon.com Inc. for the first time, though he has not been the one doing the buying, CNBC reported on Thursday.

Buffett said the purchase was made by one of his investment managers, Todd Combs or Ted Weschler, and details would be disclosed later this month in Berkshire's quarterly report of its U.S. stock holdings.

The purchase marks a U-turn for Berkshire, where Buffett has long praised the leadership of Amazon Chief Executive Jeff Bezos.

"Yeah, I've been a fan, and I've been an idiot for not buying," Buffett told CNBC.

Buffett's assistant did not immediately respond to a request for comment. Amazon did not immediately respond to a similar request.

Shares of companies often rise when Berkshire reveals its support through new stakes, even when the purchases are believed or known to have been made by Combs or Weschler, who together invest about $26 billion.

The initial impetus of the portfolio managers has in the past heralded Buffett's eventual forays into some of their investments, often in big ways.

It was Combs who in 2012 began investing in industrial and aircraft parts maker Precision Castparts Corp. Four years later, Berkshire completed its purchase of that company for $32 billion, in what remains Buffett's largest acquisition.

More recently, it was either Combs or Weschler who in 2016 began investing in iPhone maker Apple Inc.

But it was Buffett who ramped up that stake into Berkshire's largest common stock investment, more than 255 million shares, now worth roughly $53 billion.

The Amazon (AMZN) purchase adds an additional bond between Buffett and Bezos, whose companies teamed up last year with JPMorgan Chase & Co to form a new venture, Haven, to reduce employee healthcare costs.

Berkshire has more than 90 businesses in the insurance, energy, food and retail, industrial, railroad and other sectors, and often buys stocks when buying whole companies appears too expensive.

In February, Buffett called acquisition prices "sky-high for businesses possessing decent long-term prospects."

Buffett and Berkshire Vice Chairman Charlie Munger will on Saturday answer shareholder questions at Berkshire's annual meeting in Omaha, Nebraska, which normally draws more than 40,000 people.