Magistrates were told her reading was 77mg of alcohol in 100ml of breath – with the legal limit being 35mg.
During the 1990s she was one of the most recognisable faces during the Britpop era and was previously married to former Oasis guitarist Noel Gallagher.
Steven Cox, defending, said Mathews was of previous good character and had pleaded guilty at the earliest opportunity.
Mr Cox said his client had been given drinks that were “not measured properly”, with “a lot more alcohol in them than she originally thought”.
He said: “It was the first time she had spoken publicly for a number of years and she was quite nervous, and they offered her a couple of drinks.
“At the end of the evening she attempts to stay at her friend’s house, which is literally just round the corner from where they were.”
The court heard, the friend wanted to see Mathews’s new car, so Mathews went for a drive – but very soon collided with a parked car in Stret Ewyn, Nansledan – causing minor damage.
Mr Cox said whilst on her way to her friends house, Ms Mathews had “clipped” the car and caused minor damage, “stopped immediately” and was exchanging details with the owner when police arrived.
“It was a very simple drink-driving matter,” he said.
The presiding justice, Paul Shenton. said she would have been fined £660 had she not entered an early guilty plea, and that her ban could be reduced by 20 weeks if she completed a drink-driving rehabilitation course.