It was the $330 million smack heard ’round the world.

Wendi Deng Murdoch leapt to her feet to defend her husband, News Corp. Chairman and CEO Rupert Murdoch, from a demonstrator’s surprise assault at the UK parliamentary hearing yesterday.

When the protester rushed at Rupert Murdoch with a paper plate heaped with shaving cream, Wendi Murdoch (pictured), shot an open right hand at the assailant’s face, delivering a loud smack heard on live TV.

Within seconds of the slap, News Corp. shares spiked 18 cents, adding $330 million of shareholder value.

The prankish assault came during the closing minutes of the three-hour hearing about a phone hacking controversy at the News of the World.

The plate-wielding attacker was able to get within arms-reach of Rupert Murdoch at the witness table to hurl the foamy protest onto his jacket and chin. Police dragged away the assailant, identified as Jonathan May-Bowles, in handcuffs.

Rupert Murdoch, minus his jacket, resumed answering the final questions.