The account tweeted at talk show hosts and chastised Murdoch for saying Britons take too many vacations.
Twitter added a check mark graphic to the account, indicating that it belonged to the real Deng.
"And you have to wonder even more why Twitter verified this account for a full day," the fake Wendi Deng account tweeted after admitting the hoax. "I never received any communication from them about this."
The confusion may have begun when a spokeswoman for Murdoch's company, News International, told British reporters that the account was genuine. She later corrected her mistake.