Emile Hirsch Pees In Front of Nightclub

With a functioning bathroom just feet away, "Savages" star Emile Hirsch relieved himself outside a West Hollywood nightclub last night ... surrounded by strangers ... directly onto an innocent cactus.

AND HIS FACE IS PRICELESS.

Hirsch was outside Bootsy Bellows nightclub on the famous Sunset Strip -- along with his trusty red Solo cup -- when nature called ... and clearly ... the guy didn't feel like waiting in line to use the club's restroom. (It happens to the best of us.)