"beggars belief"

[varicoseveined]

I've been told that the I've been saying it incorrectly, that it should be "begs belief", not "it beggars belief".

Pedants, please help me out, who's right?

[http://www.phrases.org.uk/meanings/beggars-belief.html here]

whoops

here

You are right - beggars belief, i.e. makes a beggar of [a hypothetical anthropomorphic personification of] belief, by being so unlikely that an inordinate amount of belief would be required to accept that it is true.

Thank you!