Video of 42-year-old Deng jumping forward to smack a protester with a pie aimed at Murdoch's face quickly went viral, and numerous fan pages quickly popped up on social networking sites such as Facebook praising her quick rapid reflexes.
For the better part of the hearing, Deng - Murdoch's third wife - sat behind her husband and stepson, James, as they answered questions from British lawmakers. When a protester approached Rupert Murdoch, 80, with a foam pie he'd managed to smuggle in, one of Murdoch's lawyers - Janet Nova - quickly stepped in.
But it was the image of the long and lean Deng - clad in a prim pink blazer and polka dot pencil skirt - leaping forward to swat, open-palmed, at the man trying to attack her husband that stunned millions of TV viewers and presenters watching the events unfold live.
For what could be the first time, Deng's celebrity briefly eclipsed that of her husband. Within minutes of the attack, social media were abuzz with praise of Deng's heroic leap in defence of her husband.
A fan page on Facebook invited viewers to "express your admiration of Mrs. Murdoch's right hook," while tweets glowing with praise poured into Twitter and started "Wendi Deng" trending on the site.
Her life pre-Murdoch was not exactly tabloid material. Deng was born on mainland China, studied in the United States as a teenager and later graduated from the Yale School of Management.
Before she met her husband, Deng moved back to Hong Kong to work at Star Television, which is owned by Murdoch's News Corp.
Deng was introduced to Murdoch at a Hong Kong cocktail party in 1997 and she left Star TV before marrying the media mogul in June 1999 aboard Murdoch's private yacht, in New York.
Since then she has largely played the role of devoted spouse but is also the co-founder and co-CEO of the film production company Big Feet Productions.
She has two daughters with Murdoch - Grace, who was born in 2001 and Chloe who was born in 2003.
