Opening up in a new magazine feature about Courtney, she said the brunette star was a "loyal and fiercely loving" person to have in her life.
"There's absolutely no judgement in Court," said Jennifer, in the new issue of America's More magazine (via People).
"You'll never feel scolded. She's extremely fair, ridiculously loyal and fiercely loving."
Jennifer, 44, revealed she'd been a guest at Courteney's home many times over the years, although she didn't go into details about why she sought refuge there.
"I've slept in her guest bedroom a lot. Without giving away too much of my private stuff, all I can say is she's been there for me through thick and thin."
Jennifer and Courteney have been through plenty together, including supporting one another during divorce. Jennifer split from Brad Pitt in 2005, while Courteney and husband David Arquette split for good in 2011.
Last year, rumours surfaced that BFFs Jennifer and Courteney had drifted apart, causing us all to go, 'Noooo!' Thankfully, though, it was just that: rumours.
They showed they were as close as always with an end of year holiday to Cabo San Lucas, Mexico, while Courteney was also a guest at Jennifer Aniston and fiancé Justin Theroux's annual Christmas tree decorating party.
Meanwhile, Jennifer isn't the only Friends star gushing over Courteney in the magazine feature. Lisa Kudrow also has kind words for her former colleague.
"There's no agenda. There's no guile. There's no game," said Lisa (via E! Online). "You can trust her completely and fully. Whether I see Courteney every week or once a year, it doesn't matter. I know who she is, and I know where I stand."
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