Heather Graham celebrated her 51st birthday on Friday – and her age-defying appearance left her fans speechless.The Hangover actress certainly dressed for the occasion, wearing a figure-flattering, black floral dress with a plunging neckline.MORE: Mary J Blige stuns in a bikini to celebrate 50th birthday Sitting on a stool displaying her toned legs, Heather certainly looked sensational, and many of her fans were in agreement.WATCH: Celebrities who made headlines in 2020 "Happy Birthday!!!! Hope