The 58-year-old Bafta award-winner was sent to prison for 10 months in September after being found guilty of 15 counts of making an indecent photograph of a child.
His second application for a sentence reduction was successful at a hearing before three judges at the Court of Appeal in London yesterday. Langham, who denied the charges, was not present for the hearing.
Without the reduction, the father of five and star of satirical television drama The Thick of It was due for release in six weeks’ time.
Langham had denied the charges during his trial. He claimed he viewed the images researching a paedophile character for the BBC television series Help.