Ashlee Simpson had a super-sized fit in a McDonald's restaurant.
The 20-year-old singer's Mc-fury erupted after she tried to climb over the counter of the fast-food restaurant before launching a foul mouthed tirade of abuse at a member of staff.
Simpson who is the younger sister of actress Jessica Simpson swore at a female worker after making a hopeless attempt to get into the kitchen by clambering on the service counter before a friend had to help her down.
Fans of the singer would have be horrified to see her behaving more like a teen gone wild than one of the world's youngest singing superstars.
Footage of her outburst caught on camera and video at 1.30am on Wednesday, November 2 is sure to cause her fresh embarrassment in the wake of her recent humiliating lip-syncing scandal.
The blonde-haired star could barely stand up as she repeatedly demanded to see the manager of the restaurant in downtown Toronto, Canada.
As she pathetically clambered onto the counter she shouted: "Oh please get the manager, I would love to talk to the manager."
When a McDonald's employee asked Simpson to stop sitting on the service counter, the singer called her a "bitch" while her male companion tried to calm her down.
Her male friend tried to diffuse the potentially explosive situation and said: "She's okay, it's cool…don't worry."
Simpson then said: "I promise your manager will be nice to me."
The employee replied: "I don't think so."
"I bet you he will," she replied. "I bet you five million dollars!"
Before she could lip-synch her teeth into some French fries she had ordered, Simpson was also heard telling a customer "f**k you".
Simpson's late night munchies came after dining at the upscale Spuntini restaurant in Toronto, Canada, followed by drinks at the Avenue bar inside the Four Seasons hotel.
She had been in the city promoting her new CD, 'I Am Me,' which is currently on the top of the charts in North America.
One stunned onlooker inside the McDonald's said: "Ashlee seemed out of it. Looking at her kind of sobered us up quickly as she looked bad.
"She was swaying, staggering and could hardly stand.
"She kept leaning over the counter and her head was rocking.
"She had ordered French fries but the staff at the McDonald's were not happy with the way she was behaving.
"I heard her call the staff member a 'bitch' and then said 'I am a nice person.'
"It was awful to hear a young girl acting this way but she seemed out of control.
"She was swearing at other people and at one point told someone waiting in the queue 'f**k you.'
"People don't need to hear that kind of language and those who knew who she was couldn't believe what they were seeing.
"She was a joke and the vibe she was giving off was I'm a star and I can do what I like.
"She seemed really impatient that the food was taking a long time."
Simpson was then filmed stumbling out into the night with a friend and holding her takeaway meal after waiting for more than 10 minutes.
Last October the singer faced widespread criticism when the wrong pre-recorded vocals started playing during a live performance on the US television show Saturday Night Live.
She first blamed her drummer for lining up the wrong song but later claimed a bout of acid reflux disease forced her to fake it.
She said: "What happened to me and my voice is that I was singing from my throat and developing nodes and wasn't able to perform.
"A lot of artists use backing tracks. I was the one that got sick and got caught and I will never let myself get sick like that before performing.
"I can sing. I wasn't singing properly. I would never try to be Mariah Carey or anything like that, but I am taking voice lessons.''
But just a few months after the lip-synching scandal, Simpson was booed when she sang a song during the Orange Bowl American football game in Miami.
An online petition, signed by more than 372,000 people, also urges Simpson to stop performing.
It reads: "We, the undersigned, are disgusted with Ashlee Simpson's horrible singing and hereby ask her to stop. Stop recording, touring, modeling and performing. We do not wish to see her again. She cannot match the sound of her voice that can be found on her CDs, when she sings live. She simply yells the words (sometimes the wrong ones) into the mic. We are so sickened by her 'performing' that we are taking this opportunity to demand that she stop."
But Simpson has stated she isn't fazed by the backlash.
"You don't have to be perfect. The whole world can turn its back against you but you have to learn to believe in yourself and you can still kick ass and don't have to worry about what other people say," she said.
"I'm a new artist. I have room to grow. Look back at people like Madonna who went through hell.
Look at her now. Every artist has had struggles."
Simpson's older sister is no exception singer/actress Jessica Simpson is dealing with reports of marital problems with Nick Lachey. But Ashlee insisted all is good.
She said: "It's tough having the cameras following you around and tabloids make up stories. It surprised them to have to go through that and read those things that are so untrue. They love each other."
And asked what the public scrutiny has taught Simpson, she replied: I've learned to love myself and basically, really, just found confidence within myself.
"Other people search for a long time to find that and I'm lucky to have found that at a young age: to be proud of who I am."