We wouldn't be surprised to see Madonna, Kate Winslet, or any of esthetician Tracie Martyn's A-list clients walking out of her NYC spa. But we were kinda surprised to see a tiger.

The owner of the animal disguise? It's pop star Ke$ha, who mysteriously donned the mask to exit after her skincare appointment on Tuesday.

Well, that's certainly a creative way to hide any post-facial redness!

The star who loves to shock with her style -- which she famously calls "garbage chic" -- most recently upped the ante with a new gold tooth and some bright blue lipstick.

She's been wearing masks like these on stage during performances, but this is the first time we've seen her break one out in broad daylight.

More on Kesha here.

More on Tracie Martyn here.