Sarah Michelle Gellar pays tribute to Shannen Doherty on late star's birthday

The 47-year-old Buffy the Vampire Slayer star was a close friend of Doherty - who tragically died at the age of 53 last year following a brave cancer battle. Gellar will turn 48 on Monday and took to social media over the weekend to mark what would have been Doherty's 54th birthday. Paying tribute to the fellow Aries, the TV star shared a photograph of herself smiling alongside Doherty beside a birthday cake on Instagram.