The 'So You Think You Can Dance' host took to Twitter to express her disappointment at the Tom George eatery, which she claims was "terribly run" and urged all her followers to "avoid it at all costs".
She wrote on Twitter: "The worst featuring! Worst food! As for the manager?????? Moron!!!!! ... The most disgusting restaurant, terribly run, by a manager - who can only be described as an amateur. Avoid at all costs. #tomgeorge. (sic)"
However, the waiter saw her remarks on Twitter and sent a message back, which read: "Cat, as your server at TomGeorge I am hurt by your response to free food. I gave you respect, and I served you with love. (sic)"
And Cat ensured the waiter knew it wasn't his fault.
She added: "And as I respectfully told you, the catalogue of errors were not your fault. However, the mistakes were repeatedly not correctly rectified ...
"The food was terrible and your manager was unhelpful and rude. Respect and love should be shown to all, attention to detail is necessary too! (sic)"
Meanwhile, Cat is no doubt busy at the moment after her and her husband Patrick Kielty welcomed son Milo into the world in January 2016.
Of motherhood, she said: "I've got so much respect for all moms out there that do it. You have to juggle like crazy and have a team around you. And whether that's your family, Mom and Dad, nanny ... whoever it is, you have this team. It takes a tribe - I can totally understand that now ...
"It's really hard, but it's the best thing I've ever done too. So it's both. I would like him to do anything he wants to do. I would like him to be happy, first and foremost. I would like him to be kind, I would like him to be funny and I would like him to be smart. And any of those things are fine by me. And if dance comes into that? 100 percent. Buy him some tights, goddamn it!"