The 24-year-old star was in a pub in Soho, London, with her boyfriend when she reportedly started rowing with him.
An onlooker said to UK newspaper Daily Star: "Charlotte and her bloke were having drinks at the bar and then she suddenly started shouting at him and waving her arms around. He tried to calm her down but she just started crying."
The source added: "He looked frustrated about her ranting but after a few minutes of taking it all he started stroking her face and then gave her a massive hug. That put an end to it all and Charlotte seemed happy again."