The Scream actress revealed the cute moniker in an Instagram post, showing the close friends together with Courteney's daughter, Coco, who is also Jennifer's goddaughter.
In the post, Courteney highlighted the longevity of their friendship, writing: "Happy birthday Jenny Louise! We've known each other so long I don't even know why I call you that. I love you!"
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Courteney's post, which also featured another throwback of the duo, attracted a positive reaction from fans, with many hailing the pair's friendship.
The Office star Mindy Kaling called them a "killer duo" while another labelled them as "friendship goals", enthusing: "My two favorite women in the entire world <3. I love you both so much!!"
One passionate fan wrote: "YOUR FRIENDSHIP IS MY FAVOURITE THING IN THE WHOLE WORLD!"
Jennifer is the godmother of Courteney's daughter Coco
Courteney wasn't Jennifer's only celebrity friend to leave her a birthday message, as she received one from her ex-husband, actor Justin Theroux.
Although the former couple divorced in 2017, they have continued to champion each other.
Courteney Cox and Jennifer Aniston have been close friends for years
In the sweet message, Justin shared a black-and-white picture of the actress on his Instagram Stories, and simply captioned it: "Happy Birthday @jenniferaniston." But at the bottom, he added a heart emoji along with "You B!" as a shortened version of 'I love you B!'
Opening up about their divorce on The Ellen DeGeneres Show, Jennifer opined that all of her marriages had been "very successful, in my [personal] opinion," explaining: "And when they came to an end, it was a choice that was made because we chose to be happy, and sometimes happiness didn't exist within that arrangement anymore."
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