The Geordie Shore star arrived at Miller and Carter in a tracksuit, in the hope of grabbing some lunch at the popular eatery.
But 25-year-old Marnie Simpson was left outraged after staff refused to allow her entry over what she was wearing.
The reality TV star then took to Twitter to launch into an epic rant about what happened to her 1.05 million followers.
“Not letting one eat food at your @MillerandCarter restaurant at 2 in the afternoon because there wearing a tracksuit is shocking, [sic],” Casey Johnson’s girlfriend raged.
“All because you don’t think some 1 looks posh enough for the restaurant absolutely terrible and total discrimination against the lower class.”
And after a fan defended the restaurant’s decision saying they may want their diners to be “surrounded by decent people, not people who can’t be bothered to change out of a tracksuit,” she hit back: “How is a lovely expensive tracksuit mean I’m not suitable to eat at a classy restaurant? [sic].”
Marnie cosies up to boyfriend Casey at the MTV Single AF photocall as the pair put on a loved up display amid split rumours [Getty]
[Miller and Carter/Twitter]
The Geordie babe added: “I don’t like to wear dresses or tight clothing I like to dress comfy all the time, so your saying because I’m like this and this is my style I can’t eat in nice restaurants.”
Marnie continued to claim she felt “discriminated” against, and that “Some people don’t have money to dress fancy why should this mean they can’t eat in a fancy restaurant.”
Miller and Carter have since replied to Marnie, insisting: “We’re really sorry Marnie if we caused any offence. However, we do have dress code in place at our steakhouses.”
Despite attempting to visit a steak restaurant, Casey’s girlfriend has since shared with her fans she is debating becoming a vegan, and asked for their advice about nutrition.
Meanwhile, Marnie recently took a big step in her relationship with Casey, revealing they are moving in together.
The new couple got together after spending lots of time together during filming for MTV’s Single AF.