Tulisa was called a 'homewrecker' earlier this week by Stephanie Ward (25), who is three months pregnant with Simpson's baby. The pair already have one daughter, 18-month-old Skye Lorena, and had been seeing each other on-and-off for seven years.
"As far as I'm concerned, he has cheated on me because we hadn't broken up or anything. Tulisa is a homewrecker and has destroyed my family."
Tulisa has now taken to Twitter in a bid to clear her name.
"What is being written about me is absolutely not true," she wrote.
The star went on to say that she always likes to keep things real and doesn't intend to change that, before adding, "you are ... obsessed."
Tulisa's legal team says the singer was not seeing Danny when he was still involved with Ms Ward.
They said "any type of romantic liaison between Mr Simpson and Ms Ward was long over by the beginning of November".