Trending: Aiming for some ratings Glee with SJP

Sarah Jessica Parker will make an appearance in Glee playing the online editor of Vogue (Getty Images)

Sarah Jessica Parker is the latest star to be drawn into the Glee firmament. The former Sex and the City actress is to play the online editor of Vogue on the show, according to an announcement at the weekend. She follows in the wake of Britney Spears, who appeared as herself in 2010, and Gwyneth Paltrow, who played a frisky teacher in 2011.

It's a familiar ploy, of course: cast a name and watch the ratings go skyward. Still, despite drawing some big names in the past three years (Ricky Martin, Olivia Newton-John and Broadway stalwart Neil Patrick Harris) Glee has a way to go before it can hold a mirror to the true masters of the Guest Star Ratings Booster ploy.

Friends attracted big names like the Beverly Wilshire, including Brad Pitt, Julia Roberts and Danny DeVito. But even that pales when you consider the several-hundred-strong list who have appeared on The Simpsons – a show that can boast Paul McCartney, George Harrison and Ringo Starr in one episode alone. You're good, Glee, but not that good.