The singer teased fans via her Twitter page ahead of its premiere by asking: "Are you ready for abduction?" before posting the clip on YouTube.
The promo sees the star hurtling through space towards a destroyed planet Earth and turning a robot into a human.
Kanye West, who also features in the clip and the radio edit of the track, tweeted at the star: "Congrats friend, we did it! #sweet."
Discussing the song, Perry said in a press release: "The main gist of the song is that it is a metaphor about finding someone who is just obviously not from this world because how could they love me like this?
"Even though it is a metaphor, I'm very interested in all things futuristic. I mean, I complain every day that the hoverport has not been invented. I think it's absolutely ridiculous."
'E.T.' marks Perry's fourth consecutive number one on the Billboard Hot 100 and currently sits at 18 on the UK chart.
Watch the official video for Katy Perry's 'E.T.' featuring Kanye West below:
> Katy Perry: 'People are starting to like me'