Published Wednesday, 13 June 2012
The 31-year-old - who stars alongside Chloe Sevigny in UK drama Hit & Miss - was arrested in March after he refused to take a breath test when police found him in his vehicle in a car park in Liverpool, England.
He was found to be three-and-a-half times over the legal limit when he was tested at a nearby police station.
Armstrong appeared at Blackpool Magistrates' Court in England on Tuesday and admitted to drink driving.
He was handed a six-month driving ban and ordered to do 80 hours of unpaid work in a charity shop.
His lawyer says: "My client wishes to apologise, he was extremely intoxicated but is adamant he did not intend to drive home that day. He did not mean to be obstructive. If he was it was out of character."