Sarah Michelle Gellar Posts Sweet Birthday Message for 'Most Loyal Friend' Shannen Doherty: 'She's Everything'

EXCLUSIVE: Sarah Michelle Gellar Opens Up About 'Brave' Friend S…

Sarah Michelle Gellar on the Importance of Being an Executive Pr…

Sarah Michelle Gellar Has ‘Buffy the Vampire Slayer’ Reunion at …

Storm Reid Opens Up About ‘Challenging’ Role in ‘Missing’ (Exclu…

Tori Spelling Opens Up About 14-Year-Old Daughter's Diagnosis Af…

Wynonna Judd Reflects on Lisa Marie Presley's Death and Opens Up…

Jeremy Renner Takes His First Shower in a Week Amid ICU Hospital…

Kim Kardashian and North West Dance to Taylor Swift, Sing About …

Why Julie Chrisley Appears in Denial About Prison Time

Brian Tyree Henry and Danielle Deadwyler on Embracing Being the …

Brendan Fraser on Being 'Quite Emotional' Before Accepting Spotl…

'Extreme Sisters' Season 2 First Look (Exclusive)

North Transforms Into Dad Kanye West Alongside Kim Kardashian in…

Lacey Chabert Shares If She'd Revisit ‘Mean Girls’ Ahead of New …

'Darcey & Stacey' Season 4 Trailer: A Matchmaker and Georgi's Re…

Angela Bassett Used to Send Handwritten Cards to Promote Early A…

Gabby Windey Teases What Fans Can Expect From 'DWTS' Tour (Exclu…

‘Sister Wives’: Kody Shares His Hopes for Christine and Janelle …

'Seeking Brother Husband' Showcases Women Seeking Multiple Male …
Happy birthday, Shannen Doherty!
The Beverly Hills, 90210 star turned 46 on Wednesday, and her friend, Sarah Michelle Gellar, couldn't help but celebrate with a sweet tribute.
WATCH: Shannen Doherty Praises Pal Sarah Michelle Gellar: 'You Are a Class Act'
Gellar took to Instagram to honor her "most loyal friend," alongside a cute throwback pic of the two.
"Where do I even start with this birthday girl?!? She's everything," the 39-year-old actress wrote. "She's inspired me...well since... even before I called her a friend. But over the last year, I have watched her inspire and give hope to the world."
"I thought I knew how tough she was, but I didn't even have a clue to her power. When I think twice about leaving the house without makeup, Shannen shaved her head on the public stage. While I fiercely guard my privacy, she opened her life, her struggles, her fears and her journey to help people she has never even met," she continued. "She is a true friend to everyone."
"Shannen also has the greatest laugh in the world, which is why I chose this picture. To the fiercest, most loyal friend I know....let's party like it's your birthday!!! I love you," Gellar concluded her touching message.
EXCLUSIVE: Shannen Doherty Gives Health Update, Admits She Doesn't See Herself as an Inspiration
ET caught up with Gellar last week in New York City, where she gushed about her "incredible" friend.
"Shannen's incredible. What she's done for other women going through it is... so brave, and that's what real bravery is, is to go through the hardest part of your life and show people, it's OK to be scared," Gellar said of Doherty's willingness to share her breast cancer battle. "And it's OK to be vulnerable, and you can do it."
See more on the pair's friendship in the video below.