Singer Tulisa Contostavlos was "upset but not angry" after a confrontation with a celebrity blogger in Chelmsford, her tour manager has told a court.

Writer Savvas Morgan said he suffered swelling to his eye after an alleged incident involving the 25-year-old in Chelmsford, Essex, last year.

But the ex-N-Dubz star and former X-Factor judge has claimed she did not attack him and has been the victim of a vendetta, saying Mr Morgan had a "strange obsession" with her.

Contostavlos denies an assault charge linked to the alleged altercation at the V Festival last August.

The star is on trial at Chelmsford Magistrates' Court with her assistant, Gareth Varey, who is accused of threatening behaviour, which he also denies.

Her tour manager, Drew Lyall, said he had put in arm around her after witnessing the aftermath of the incident.

Singer Tulisa arriving at court.

Mr Lyall, who told the court he had assisted Contostavlos on hundreds of occasions, added: "She was very upset and briefly mentioned it was a guy who had been hounding her or harassing her for a very long period.

"She hadn't mentioned any particular individual before the incident, I had never seen him before.

"She was calm. She was just a little bit upset."

Other celebrities, including singer and rapper Misha B, Sugababes singer Mutya Buena, singer Alexandra Burke and rapper Wretch 32, all witnessed the incident but have not given evidence.

Contostavlos told the court that Mr Morgan had had a "vendetta" against her since an incident in which she asked security to remove him from a VIP area at the Whisky Mist nightclub in London's Mayfair.

She also outlined her suspicions that Mr Morgan was involved in the release of a sex tape of her online.

But she claimed she had no grudge against him, saying: "He was one of many."

Mr Morgan told the court that Contostavlos raised her fists in the air and was swinging her arms in a backstage area at the festival.

"Everyone was jumping around trying to get at me, there was a lot going on," he said.

Prosecutor Matthew McNiff said the incident happened at 12.30am on August 18 as Mr Morgan was about to leave. He said Contostavlos accused Mr Morgan of stalking her, and swore at him.

Contostavlos and Varey, 28, both of Royal Drive, Friern Barnet, north London, are both on unconditional bail.