Reverse video clip (invert? Mirror?)

Not sure the correct term, but I need to make a clip play FOWARD, but with the image reversed.  That is, if I have a guy walking foward from left to right, I want him to still walk foward BUT from right to left.

I know I've done it before, but can't remember or find any info on it.  I can do it in AI, PS, AE, but grrrr... PR??  Can't remember.

Please help!  I'll give you a high five if you can get it to me in the next hour! haha!