Girls Aloud star Nicola Roberts reportedly had a public argument that turned physical on a night out in Liverpool over the weekend.

Early on in the evening, the pair were spotted kissing and cuddling in the VIP section of Mosquito in the city - but things quickly turned vicious.

An onlooker told the Sun: “It was a really nasty row.”

“They began the night all huddled up in a corner of the VIP section, snogging each others’ faces off. Then they began rowing and it really kicked off. They were pushing, pulling and shoving each other and she was in floods of tears.”

“Nicola was giving as good as she got. She didn’t care who was watching - and they had quite an audience.”

“There were quite a few Everton footballers hanging around. They had been showing her a bit of attention, I don’t know if that was a factor.”

A friend of Nicola’s added that this type of thing is far from unusual for the pair - who also had a public row at the NME Awards earlier this year: “They’ve only been together about six months but it’s a very intense relationship.”

“When they’ve had a drink they’re up and down like anything. One minute they’re snogging and the next they are having a blazing row.”

“They do get physical. They’re not trying to hurt each other but they do push and pull each other around.”

“It’s all very public too. Nicola clearly adores him but we’re worried a relationship this new can be so volatile.”