Cox shared a photo of herself twinning with Aniston. The picture shows the pair wearing matching glasses and Cox holding up a hair extension to her head in Aniston's exact shade.
"No matter how hard you might try... there's only one Jennifer Aniston. Happy birthday my dear friend @jenniferaniston! I love you!" Cox captioned the post.
Kudrow posted a throwback photo of Aniston.
"Always beautiful and keeps getting more beautiful. Happy birthday @jenniferaniston I love you. Also, I JUST don't know how to post a picture right," she wrote.
Perry, who joined Instagram last week and now has over 4.9 million followers, also shared a throwback photo.
"Happy birthday, Jenny!!!" he wrote.
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Aniston's ex-husband Justin Theroux also wished the actress a happy birthday, writing, "Happy birthday B" on Instagram Stories.
Aniston discussed aging in Hollywood in an interview with actress Sandra Bullock for Interview magazine published Tuesday. The pair celebrated the fact that the entertainment industry has started to expand its "horizons" for women of all ages.
"Think of the generation ahead of us. So many of those women were put out to pasture when they were 40, and the fact that we get to still be working and are actually coming into our most creative adventures ever at this point in our life -- we're rewriting that narrative that society sort of plastered on us," Aniston said.
Aniston said she's looking forward to doing more on both a work and "spiritual evolvement" level.
"It's not so much what I see myself doing, but it's more like a little screenshot in my brain, where I hear the ocean, I see the ocean, I hear laughter, I see kids running, I hear ice in a glass, I smell food being cooked. That's the joyous snapshot in my head," she shared.
Aniston most recently starred in the Apple TV+ series The Morning Show. She will star in the upcoming film The Fixer.
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