The Celebrity Gogglebox stars were in tears as they watched Supervet Noel Fitzpatrick try to save his own dog.
Friday's show saw the celebrities gripped by the plight of elderly Border Terrier Keira after she was run over outside her famous owner's surgery.
As the upsetting scenes unfolded - including the dog yelping in pain - it was too much for some.
"I just love animals, I don't like seeing animals in pain, Denise van Outen's partner Eddie said.
"It breaks me. I can't watch things like this."
Sir Tom Jones was hopeful Keira would make it through the operation.
"She's bound to pull through," the singer said matter-of-factly. "You can't have a dog dying on the TV."
As Noel performed risky surgery in a bid to help Keira walk again, actress Georgia Taylor noted: "It's like DIY SOS this when they get the drills out."
"Oh man this is harsh," her friend Sunetra Sarker added.
Radio star Roman Kemp said: "Oh God, that noise" as Keira cried, while his dad, Spandau Ballet star Martin Kemp, clutched his own dog and looked tearful.
The celebrities were delighted to learn Keira was on the road to recovery at the end of the episode and walking again.
TV presenter Clare Balding, watching with her wife Alice Arnold, had been unable to look and was afraid the show would have an unhappy ending.
Alice told her: "See, I told you it wouldn't have a sad ending, because it's Supervet!
"They wouldn't show you if it wasn't going to be happy."
Dabbing her eyes, Clare pointed out: "They do though sometimes and it doesn't always have an end like that."
Celebrity Gogglebox is on Channel 4 on Fridays at 9pm.
