The accusation against Ambassador Sherry Rehman is the latest in a string of controversial blasphemy cases in Pakistan, a largely Muslim nation whose name translates as Land of the Pure.
According to Pakistan's blasphemy laws, anyone found to have uttered words derogatory to the Prophet Muhammad can be put to death. Those who are accused are sometimes lynched by mobs even before they reach court.
Rehman has already faced death threats from militants after calling for reforms to the country's anti-blasphemy law, according to court documents. Two politicians who suggested reforming the law were assassinated.
The case against Rehman was brought by businessman Muhammad Faheem Gill, 31, who said that the comments Rehman made about the law on the Pakistani talk show in 2010 were blasphemous.
"I've been trying to get this case registered for the last three years, ever since I saw that TV show," Gill told Reuters. "I've even gone to the highest court. I'm glad that action will finally be taken now."