Jilly Johnson said she got to know Clifford when she was 17 in the mid-1970s after meeting him at "glamorous parties". She told London's Southwark Crown Court the publicist acted as a "mentor" for free as she was offered acting work on television and in the theatre.
Clifford, 70, from Hersham in Surrey, is standing trial accused of 11 counts of indecent assault against seven girls and women.
Asked by defence barrister Richard Horwell QC how Clifford behaved towards her, Ms Johnson said: "Respectfully. Nothing untoward or inappropriate. Literally as a mentor, as a guide, a great help. He was marvellous." Ms Johnson, who told the court she would dress "provocatively" in her late teens, said Clifford had never behaved inappropriately towards her. She added: "I think he is an honourable man. I do not feel he could be, in any way shape or form, not that. He's very much a gentleman."
The witness, who said she appeared on light entertainment shows with Jim Davidson and Des O'Connor, told the court she would visit Clifford in his office and call him for advice on her career.
She told the jury: "I would get into a rut or a dead-end alley and pick up the phone and say to Max I have been offered this." Ms Johnson said he gave "sound advice" and helped her make the "transition" from model to get parts in television comedy programmes.
The trial continues.