Thamsanqa Jantjie told South African newspaper The Star that he suffered a schizophrenic episode while on stage during the event.
Jantjie said: “There was nothing I could do. I was alone in a very dangerous situation.
“I tried to control myself and not show the world what was going on. I am very sorry, it’s the situation I found myself in.”
Jantjie claims to have the requisite qualifications for being a sign language interpreter, and works for an interpreting company that paid him 85 dollars (£52) for interpreting Tuesday’s event.
Mr Jantjie did not address allegations by sign language experts that he faked the interpretation, which was broadcast around the world.