Courteney Cox posted special birthday wishes for Jennifer Aniston to mark her turning 52 - and revealed her usual nickname in the process.
She posted a throwback photo of her close pal and former Friends co-star to Instagram on Thursday, in a snap which also included Cox's daughter Coco who is Aniston's godchild.
Cox wrote in the caption: "Happy Birthday Jenny Louise! We’ve known each other so long I don’t even remember why I call you that.”
Watch: Justin Theroux wishes ex-wife Jennifer Aniston a happy birthday in sweet Instagram post
The 56-year-old added: “I love you !”
Adding to the mystery, the moniker doesn't appear to derive from Aniston's middle name either as it's Joanna.
Other stars paying tribute included her The Morning Show co-star Reese Witherspoon who also had a guest turn in Friends as Aniston's Rachel Green's younger sister Jill.
"Happy birthday to my #morningshow co-host! 💫" the Legally Blonde actor captioned the photo of the pair on set at The Morning Show.
"From Green sisters to news anchors, we always manage to find time to talk and laugh about every topic under the sun. Just one of the many reasons why I feel so lucky to know you on and off the screen."
Aniston's ex-husband Justin Theroux also wished her a happy birthday with a black and white photo of the actor on his Instagram Story.
"Happy birthday @jenniferaniston," he wrote at the top of the image, adding "[Love] you B!" at the bottom.
With additional reporting by PA.
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