Police confirmed they had “received information concerning the alleged supply of illegal drugs at a central London location”.

A statement from Met Police said: “Officers from Westminster have arrested two people – a 35-year-old man and a 24-year-old woman – on suspicion of supplying class-A drugs. They are in custody at a Central London police station.”

According to allegations from an undercover reporter working for The Sunday Sun, former N-Dubz singer Contostavlos, 24, offered to obtain cocaine for the reporter through her contacts, saying, “Half my phone book sells it. Of course I can get it for you. Half the guys I know are drug dealers. One’s a massive cocaine dealer. He’s my best friend. He’s a gangster – he’s my gangster.”

“Whatever you want, he’s got it,” the singer said, according to the paper, offering half an ounce of cocaine sold for £820 under the code term ‘white sweets’. The alleged incident took place at London’s Dorchester Hotel.

Tulisa resigned from her job as a judge on X-Factor yesterday.

“I’d like to thank everyone on The X Factor for two amazing years.” said Contostavlos on her Twitter feed.

However, despite the speculation, an X-Factor spokesperson said that “the two stories are unconnected.”

In her recent autobiography, Contostavlos claimed that she was a role model for her young fans. “Why am I a role model? Because I have been myself. I’m an inspiration for Broken Britain. I didn’t want to be seen as a negative role model for young kids. I felt like I had a responsibility to behave in a certain way.”