The trial heard how Robertson, of Carbeth in Stirlingshire, raped a woman on one occasion between 2018 and 2019 as well as a separate sex assault.
The pair came to know each other from working together on River City.
The woman said she did not want anything sexual to happen, but believed Robertson did.
The relationship became intimate, but the woman later told Robertson she wanted their relationship to go back to being platonic.
She said one evening she was at his home in Glasgow’s Tradeston and planned to sleep on the sofa, but Robertson allegedly told her she could join him in bed as “nothing would happen”.
However, the witness said that the actor instead “had sex” with her.
She did not say anything to Robertson at the time, but said she did not participate in what happened and she did not want it to happen.
During another incident in Glasgow, the witness claimed Robertson had been upset about the “sexual aspect ending” and kicked over a table, breaking a vase.
The court heard Robertson later went into the woman’s bed. She also got in to go to sleep.
She also described an earlier incident when Robertson carried out a sex act on her and she “just waited for it to be over”.
He was also found guilty of engaging in a course of abusive behaviour against her.
Robertson was put on the sex offenders’ register and will be supervised for a further three years upon his release from jail.
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