The hedge fund billionaire known for seizing an Argentine navy vessel as partial payment for a debt is taking aim at AT&T — the telecom behemoth that also owns HBO and CNN.

Paul Singer’s Elliott Management hedge fund sent a shot across the bow of AT&T Chief Executive Randall Stephenson on Monday when the firm revealed a $3.2 billion stake and demanded a series of changes to boost the stock price.

In a letter to AT&T’s board, Elliott blasted Stephenson’s leadership, saying he has overseen a decade of underperforming returns for stock holders. The letter blamed the disappointing returns, in part, on Stephenson’s aggressive strategy of acquisitions, including the 2014 purchase of satellite TV company DirecTV for $67 billion.

The letter claimed that if the company follows Elliott’s advice, AT&T stock will soar to more than $60 a share — a price that would represent a 65 percent upside to the current stock price. AT&T’s shares rose 1.5 percent Monday, to close at $36.79.

Elliott called on the Dallas conglomerate to get rid of businesses that don’t make sense, like DirecTV. And while Elliott didn’t name Stephenson directly, the firm demanded the board to take a closer look at its management team.

In a statement, AT&T said it’s reviewing the letter and that the board looks “forward to engaging with Elliott.” But behind the scenes, the salvo prompted AT&T to hire Goldman Sachs to defend itself — suggesting a battle for control could be in the cards, sources said.

Indeed, the activist hedge fund, known for battling large companies like Samsung, plans to launch a battle for board seats as soon as this year if it doesn’t get its way, according to a source with knowledge of the situation. The window for board nominees opens Dec. 28 and ends Jan. 27, the source said.

Elliott also raised questions about AT&T’s $85 billion acquisition of entertainment giant Time Warner. That deal closed earlier this year, giving AT&T control of “Game of Thrones” and “Big Little Lies” maker HBO.

The hedge fund chastised AT&T for the “alarming executive turnover” at its newly acquired media properties.

As The Post has previously reported, HBO staffers have clashed with their new boss, John Stankey, who AT&T put in charge of its freshly acquired entertainment properties.

“The activist playbook is for Elliott to embarrass AT&T’s leaders and then get them to do something,” a media expert who has battled activists said.

In 2012, Elliott made headlines when he seized a prized Argentine navy vessel as part of his years-long quest for $1.6 billion he was owed for defaulted bonds he purchased.

The company has also waged battles with South Korean technology giant Samsung and gas station chain Hess.

Oddly, the hedge fund’s latest battle against AT&T got a shout-out from President Trump, whose Department of Justice unsuccessfully sued to stop AT&T’s acquisition of Time Warner.

“Great news that an activist investor is now involved with AT&T,” the president tweeted Monday.