Pussycat Dolls singer Ashley Roberts said she "didn’t feel safe" and was left "looking over my shoulder" over the "scary" behaviour of a man who believed he was her boyfriend.
Lewis Langley, 47, was handed a restraining order after blowing kisses, smiling, and giggling at the former Strictly Come Dancing star, 41, as she came and went from the radio station where she works in Leicester Square, central London in the UK.
He was dubbed "the martial artist" by Global Radio security guards for performing exercise routines, including high kicks, jogging on the spot and diving headers.
Croydon Crown Court heard how he loitered outside the building – once claiming Ms Roberts had some of his clothes and was communicating with him by social media "in her own special way".
Prosecutor Alex Alawode said: "The defendant believed he was in a relationship with Ms Roberts, being a former member of girl band Pussycat Dolls and currently a radio DJ in central London."
Appearing by video-link, wearing a pink blouse, on Thursday, she said she saw Langley around 15 times between May and October last year.
Ms Roberts, who with fellow Pussycat Dolls Nicole Scherzinger, Carmit Bachar, Jessica Sutta and Kimberly Wyatt, released hits including Don’t Cha and Stickwitu, told the court how Langley made her feel "very uncomfortable".
"I didn’t feel safe," she said. "His behaviour was scary, smiling to himself, blowing kisses."
Langley was arrested in August last year, when the police told Ms Roberts he had mental health issues and believed he was in a "romantic relationship" with her, the court heard.
He was detained under the Mental Health Act but began returning to her workplace in October last year, by which time security measures had been stepped up and she was being escorted to and from her car.
"I got in the car and the car started to drive along," Ms Roberts said.
"I looked to my right and he was standing on the sidewalk blowing me kisses.
"He was blowing them at the window to my car."
Asked how Langley’s behaviour made her feel, Ms Roberts said: "I just didn’t feel safe, I felt uncomfortable walking around, I was looking over my shoulder just to make sure he was not around or following me."
Langley, of Thornton Heath, south London denied stalking Ms Roberts between May and October last year. He was also accused of repeatedly attending an address in Borough, central London, he believed was Ms Roberts’s home, where he would sit on a chair staring into the building.
But prosecutors offered no evidence on a further charge of stalking the building’s manager Anna Olivera after the complainant refused to give evidence if she could be seen by journalists in court.
Hesham Puri, defending, said that although Langley’s "odd" behaviour may have been "unattractive" and "irritating", he never tried to approach or talk to Ms Roberts and it did not cause the "serious alarm or distress" necessary to find him guilty of stalking.
District Judge Nigel McLean acquitted Langley of stalking, telling him it was a "very serious offence, which carries significant sanctions" and must be proved to a very high standard.
"On the admissible evidence available to the court, the Crown has failed to reach that requisite standard," he said.
But the judge made a three-year restraining order, banning Langley from contacting Ms Roberts directly or indirectly or going within 50 metres of Global Radio.
Langley has been remanded in custody awaiting sentencing for a breach of a non-molestation order in relation to his ex-partner.