On the matter of celebrity journalism, few can speak with greater authority than Hugh Grant, who has found himself the subject of more than a few tabloid exclusives since joining the Hollywood A-list.

Now the actor and paparazzi favourite has revealed that he turned the tables on one former News of the World hack, wearing a concealed microphone to record the reporter alleging that Rebekah Brooks, the paper's former editor, "absolutely" knew about illegal phone-hacking.

Writing in this week's edition of the New Statesman, guest-edited by his former partner Jemima Khan, Grant says he met the journalist, Paul McMullan, when his car broke down in Kent shortly before Christmas and the reporter-turned-publican, who had been following him in the hope of photographing him, offered him a lift. McMullan, formerly deputy features editor at the News of the World, is one of a number of journalists who have spoken out alleging widespread phone-hacking at the paper.

Last week, Grant returned to McMullan's Dover pub wearing a wire. "I wanted to hear more about phone hacking and the whole business of tabloid journalism," he writes. "It occurred to me just to interview him straight, as he has, after all, been a whistleblower. But then I thought I might possibly get more, and it might be more fun, if I secretly taped him. The bugger bugged, as it were."

McMullan tells the actor that eavesdropping on phonecalls had "started out as fun", but after it was made illegal in 2001 to buy a digital scanner, reporters were obliged to "find a blag to get your mobile [records] out of someone at Vodafone".

The full account of his interview appears in this week's New Statesman.