Farrah Abraham Falls While Arriving at Fashion Show

Farrah Abraham on all four is par for the course ... except not in front of hundreds of peeps at a fashion show. Somewhere, a casting director's light bulb probably just flashed.

The former 'Teen Mom' star, her daughter Sophia and a bunch of her friends hit up The MacArthur Monday night for the Art Hearts Fashion show in L.A. All seemed to be going as planned ... everyone looking to the nines. Then Farrah started trippin' ... literally.

Farrah took a hard spill walking up the stairs ... and judging from everyone's sheer shock, Farrah went down hard and fast. Hard to tell ... but looks like the culprit coulda been her shoelaces. And when you're Farrah, you've apparently got friends in low places ... who can come down and tighten those shoelaces.

Just when ya thought it was safer to walk, right?