on top of the world, at the top of the world

[joham]

I ran across this sentence in a test paper: Pop singer Peng Tan has tasted the joys of being at the top of the world.

I thought we should use 'on top of the world' instead of 'at the top of the world'. Am I right?
I searched the reference.com web and got 1440 results for 'on top of the world' and only 125 results for the other.

Thank you very much.

[susiedqq]

"Being on top of the world" is an expression used to describe someone being very successful or at his/her best - and everyone knows it OR feeling very good, euphoric.

When her book was published, she was on top of the world.

She felt on top of the world at her birthday party.

Being "at" the top of the world means you are standing at the North Pole!