London, England (CNN) -- Singer George Michael was released from prison Monday after serving nearly a month for driving under the influence of drugs, the British Ministry of Justice said.
He was sentenced in September to serve eight weeks at Highpoint Prison in Suffolk, with District Judge John Perkins saying he must serve at least half the sentence.
The pop singer pleaded guilty after crashing his car into the front of a north London shop in the early hours of July 4, damaging the building's facade but causing no injuries.
The charge would normally carry a 12-week sentence, but Judge Perkins said he gave Michael credit for his guilty plea and his remorse.
Prosecutor Jonathan Efemini told the court at a sentencing hearing last month that when police got to the car, they found Michael wide-eyed and appearing "spaced out." He was also carrying two marijuana joints, Efemini said.
Michael told police he had left home at 1:30 a.m. to see a friend but couldn't remember the route. He said he had taken a sleeping pill that had been prescribed eight days earlier and admitted smoking cannabis earlier in the night, Efemini said.
Michael, whose real name is Georgios Panayiotou, was sentenced for the formal charge of driving while unfit through drugs. His sentence included a fine of 1,250 pounds, or $1,925, and a five-year driving ban.
He already reimbursed the shop owner in person for the damage, Efemini said.
Despite showing leniency, the judge mentioned Michael's two previous drug arrests, saying, "It does not appear you took proper steps to deal with what is clearly an addiction to cannabis."
Michael was found guilty in 2007 of unfit driving through tiredness and prescription medication and received a two-year driving ban.
He also received a caution for cannabis in 2006 and a caution for cannabis and crack cocaine in 2008, Efemini said.
He was arrested again the following year near Hampstead Heath park in north London and cautioned for possession of a controlled substance.
Michael's defense attorney said his client had "profound shame and horror" at having committed another offense.
"He acknowledges and recognizes that his actions ... had the effect of causing other road users to be in danger," Mukul Chawla told the court, "and that stark fact caused him to be greatly ashamed."
CNN's Carol Jordan and Melissa Gray contributed to this report.