Fiona Apple is canceling her upcoming South American tour due to the declining health of her dog, Janet.

No, we're not kidding ... and no, we don't have any problem with her decision, especially given the heartfelt letter she penned to fans and posted on her Facebook page Tuesday (November 20), in which she calls her beloved dog "My best friend and my mother and my daughter, my benefactor" and "the one who taught me what love is."

"I got her when she was four months old, I was 21 then, an adult officially, and she was my child ... Janet has been the most consistent relationship of my adult life, and that is just a fact," Apple wrote. "She slept in bed with me, her head on the pillow, and she accepted my hysterical, tearful face into her chest, with her paws around me, every time I was heartbroken, or spirit-broken, or just lost, and as years went by, she let me take the role of her child, as I fell asleep, with her chin resting above my head."

Apple added that Janet suffers from Addison's disease, a rare endocrine disorder in which the adrenal glands do not produce sufficient steroid hormones, and needs frequent Cortisol injections to deal with the condition. Janet had been coping for years, but when Apple returned from the most recent leg of her U.S. tour in support of the The Idler Wheel ... album, she noticed a marked difference in the dog's health ... and now, she fears she can't leave her "best friend's side."

"If I go away again, I'm afraid she'll die and I won't have the honor of singing her to sleep, of escorting her out. Sometimes it takes me 20 minutes to pick which socks to wear to bed. But this decision is instant," she wrote. "I will not be the woman who puts her career ahead of love and friendship ... I just can't leave her now, please understand."

Apple recently posed with a portrait of Janet in a New York Times profile, and has taken a cut-out of the dog onstage during Idler Wheel shows. Her South American tour was set to kick off on November 27 in Porto Alegre, Brazil. At press time, there has been no word on when those dates will be rescheduled, but Apple promises she'll make them up, closing the letter with a solemn "I'll be seeing you."

Do you support Apple's decision to spend time with her ailing pooch? Let us know in the comments below.