Fans may know Jennifer Aniston as Rachel Green, but her Friends co-star and best friend Courteney Cox has a different name for the actress. Courteney shared photos of her and Jennifer in honour of the The Morning Show star's 52nd birthday. She wrote in the caption of the Instagram post, "Happy Birthday Jenny Louise! We've known each other for so long; I don't even remember why I call you that. I love you!" Jennifer's middle name is not Louise – it's Joanna – so the origin of this particular nickname is a mystery to fans as well. However, followers loved getting this sneak peek into the Friends co-stars friendship. This isn't the only time we've seen their friendship on Instagram. In February of last year, Courteney celebrated her pal's birthday in a cute way: by stealing her look. The Cougar Town alum wasn't the only person to throw Jennifer love this year on her birthday. Jennifer's ex-husband Justin Theroux also wished her birthday by posting a photo of Jennifer.