Heidi Montag responds to sex tape reports

Heidi Montag has reportedly said that she is "unaware" of the existence of a sex tape featuring herself.

It was recently claimed that The Hills star's estranged husband Spencer Pratt has a video of himself and Montag in his possession and is looking at the possibility of selling it.

Speaking to Life & Style, Montag insisted that she knows nothing about the tape, although she seemed to suggest that there was a possibility one could exist despite her lack of knowledge.

"I'm not aware of his filming me, but I wouldn't put it past Spencer. He's a sneaky guy and has little cameras everywhere that he got from China," she told the magazine.

The 23-year-old - who also said that she is "desperate" for a breast reduction - added that she is "mortified" that people could see her pre-surgery body if the tape does exist and is made available to the public.

Montag and Pratt announced their separation in May.