Fans of the BBC documentary were outraged to learn that the ice nest where polar bears were filmed was a man-made, and that commentary by "national treasure" Attenborough was carefully scripted to avoid making explicit references to the cub's birthplace.
The birth of the polar cubs was a magical centrepiece to episode five of Frozen Planet, with viewers invited into the womb of ice where "the newest polar bears in the world" were seen snow white and blinking.
The BBC defended its treatment of the footage, with the show's producer Kathryn Jeffs explaining that it was both impractical and dangerous to film the polar bears inside the ice nest.
Sir David Attenborough supported her defence, adding that the decision was made for "the safety of the animal".
He told ITV1's This Morning: "If you had tried to put a camera in the wild in a polar bear den, she would either have killed the cub or she would have killed the cameraman, one or the other."
Although Frozen Planet has been criticised for not making its explanation transparent, Attenborough said talking about the zoo during the show's would have ruined Frozen Planet's atmosphere. He added: "It's not falsehood and we don't keep it secret either."