In an article published on the Pottermore website on Tuesday written in the form of a gossip column, Harry and his friends reunite at a tournament of the broomstick-riding game quidditch.

Harry's red-haired friend Ron Weasley is said to be thinning on top, while the 1500-word story raises questions over the state of Harry's marriage to Ron's sister Ginny Weasley.

Millionaire author Rowling meanwhile gives a teaser when she writes that Harry - played by the actor Daniel Radcliffe in the films spawned by the book - sports a new scar on his cheek to go with the lightning-shaped one on his forehead.

"About to turn 34, there are a couple of threads of silver in the famous Auror's black hair but he continues to wear the distinctive round glasses that some might say are better suited to a style-deficient twelve-year-old," the story says.

There is a further hint of things to come when the story asks whether the "chosen one" might be "embroiled in fresh mysteries that will one day explode upon us all, plunging us into a new age of terror and mayhem".

Rowling has sold more than 450 million copies of the Harry Potter books - which tell the story of the young wizard and his friends at the Hogwarts school of magic - while they have also spawned a string of hit films and the Pottermore website, an interactive site for fans begun in 2011.

Her latest piece is written in the form of a gossip column by Rita Skeeter of the Daily Prophet, a character from the Potter books who draws on the author's own vocal criticisms of British tabloid journalism.

In the story, Harry brings his two sons James and Albus - last seen in the epilogue to the seventh and final instalment Harry Potter and the Deathly Hallows - to see the "2014 Quidditch Cup".

But the story hints at problems in his marriage to Ginny, now a journalist covering the tournament, asking: "Are cracks beginning to show in a union that the Potters are determined to promote as happy?"

Meanwhile Ron Weasley - played by actor Rupert Grint in the films - has gone to work at the family magic shop but the columnist whispers about "mental illness".

Ron and Hermione Grainger - played by actress Emma Watson - also have two children in the new story, son Hugo and daughter Rose.

Hermione has enjoyed a "meteoric rise" to Deputy Head of the Department of Magical Law Enforcement but the gossipy writer asks: "Does Hermione Granger prove that a witch really can have it all? (No - look at her hair.)"

There is no sign however that Rowling has acted on her admission earlier this year that she should have married off Hermione to Harry, and that Ron and Hermione would probably have ended up in marriage counselling.

The new piece is part of a series about the Quidditch Cup - a nod to the football World Cup in Brazil - that are set to appear on Pottermore. The final article will be published on Friday and will see Ginny Potter cover the cup final, between Brazil and Bulgaria.

Rowling has been keeping busy since the seventh and final novel in the series was published in 2007.

She published her first adult novel, The Casual Vacancy, to mixed reviews in 2012 and has also released two big-selling crime novels under the nom de plume Robert Galbraith.

She announced last year that she will make her screenwriting debut by penning a series of spin-off films set in the Potter world, starting with Fantastic Beasts and Where to Find Them.