Mary-Kate: World's Youngest "Golden Girl"

From the looks of her rainbow muumuu dress thing, Mary-Kate Olsen's true twin is ... Bea Arthur! Thank you for being a friend?!

Done with her 2006 witch boots and oversized '70s shades, the 21-year-old wannabe Snowbird unleashed her latest accessories on the innocent public at a NYC event on Wednesday -- a bile-colored clutch and a retired Moscow socialite's aerobics headband. Oy!

Afterwards, Mary-Kate enjoyed cheesecake and kibitzed with Dorothy, Rose, Blanche and Sophia on the lanai.