Reacting to fans who complained about Pink scrapping the show in Birmingham, England, last month on doctor's orders, Clarkson sent out a message of solidarity to her friend from WhoSay: "How dare you only work 364 days this year. I can't believe you got sick. That never happens to anyone ….ever. You're so lazy."
Clarkson, 31, added the super-long hashtag: "Name one person that has her schedule, sings while flying and is a mom."
The "American Idol" star continued, "Seriously people. Tired of seeing everyone giving her crap. We're all human. Relax."
Not that Pink takes much from anyone, the 33-year-old singer defended her decision last week in a long message to fans that was both apologetic and irate.
"The next time I schedule dates- ill [sic] have to say to myself-'if, God forbid I have to cancel one show, those fans will turn on me like rabid dogs and question the moral fabric of my character.' For the loyal and understanding fans-I am so so sorry if I've hurt you in any way. For the rest of you-Kindly kiss my entire almost back to healthy a**."
Pink told fans she was suffering from an ear and respiratory infection, as well as rotavirus, a condition that most frequently affects young children and causes fever, vomiting, diarrhea and abdominal pain.
The two singers have been vocal about their support for each other in the past.
When Clarkson won a Grammy earlier this year, Pink tweeted, "Congrats to Kelly Clarkson for the award and that loveable speech.
Clarkson tweeted to Pink, "this just made my night! I love you!"