Ashley Roberts' alleged stalker Lewis Langley is said to have thought the Pussycat Dolls star was his girlfriend, a court has heard.
Mr Langley, of Thornton Heath, south London, is accused of loitering outside Miss Roberts' work place in a trial at Croydon Crown Court, which begun today.
The 47-year-old is said to have regularly attended her workplace early in the morning as she arrived.
Prosecutor Alex Alawode told the court how Mr Langley was "captured on CCTV on a number of occasions and was seen performing exercise routines outside the building by way of high kicks or running", PA news agency reports.
Mr Langley is accused of waiting nearby her workplace until she left.
Sherlock Holmes Museum boss wins fight to evict brother from home in 10-year rowMr Alawode said on one occasion Mr Langley was "following her as she got into her waiting vehicle as she left work".
He added of an alleged occasion in October: "[Mr Langley] He was following alongside that vehicle and blowing kisses into the window, believed to be directly aimed at Ms Roberts."
The court also heard how Mr Langley is said to have allegedly attended an address in Borough, central London, where he is said to have believed Miss Roberts lived.
Mr Langley is accused of sitting on a chair and stare into the building.
The alleged stalking campaign is said to have taken place between May and October last year.
He was arrested in August last year and detained under the Mental Health Act. However, Mr Langley is accused of returning to the building where Miss Roberts worked in October last year.
Mr Langley is said to have told police he was in a relationship with Ms Roberts, with whom she had made arrangements over social media but claimed she was ignoring him, the court heard.
Prosecutor Mr 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."
He added: "The defendant states he was not stalking the complainant but had good reason to be at those locations."
Mr Langley, 47, was charged with two counts of stalking without fear/distress/alarm, which he has denied.
Protesters planned to kidnap King Charles waxwork and hold it hostageHis trial begun at Croydon Crown Court today following a pre-trial hearing last December.
The trial continues.