Whoops! Oprah Winfrey plugs Surface – from her iPad

Microsoft must have thought it had scored something of a coup by persuading the chat show queen to endorse its new Surface tablet.

But it looks as if it could have been a bit of an own goal. While the media mogul has been gushing for weeks about the Surface, which she has said is the Mercedes of the tablet world and named as one of her Favourite Things of 2012, her latest tweet has been rather embarrassing for Microsoft.

From her official Twitter account, she wrote: “Gotta say love that Surface! Have bought 12 already for Christmas gifts.”

Great for Microsoft you would think, but the problem was she tweeted from her iPad – and the gaffe was immediately spotted by the world’s technology press, websites and blogs.

It’s a huge blow to Microsoft which has spent $1.5bn and enlisted a string of celebrities to help it sell its latest gizmo, a laptop/tablet hybrid the firm hopes will be a true competitor to the iPad. Other stars who have endorsed Windows 8 include singer Gwen Stefani and actress Jessica Alba.

The blunder provoked a huge response across the web, with Alex Wilhelm from The Next Web saying: “She does have legions of fans, making her an effective marketing channel for Microsoft. Except for when the narrative around her promotion is tossed on its head by a foolish, and utterly avoidable mistake – Surface ads, now brought to you by iPad.”

But others claimed the slip up wasn’t really important to Microsoft’s marketing strategy. “We have to ask,” says Mashable, “does that really matter?”

Brian Anthony Hernandez for the site points out: “Technology users own more than one gadget – often made from different companies. And, as my colleagues point out, people use an iPad differently than the Surface. And for Oprah, that’s no different. She did put the iPad on her Ultimate Favorite Things list in 2010.”

Whether the tweet makes any difference when it comes to Surface sales will be impossible to tell but Microsoft certainly won’t be happy about how it has gone viral.

It comes after problems were reported from some of the first customers to buy Surfaces, with some saying the Touch cover was splitting only a few days after they made their purchase.

The firm will simply be hoping potential consumers remember what Oprah said previously about the tablet in O Magazine: “The Surface, Microsoft’s first tablet, feels like a Mercedes-Benz to me, People! The full-size keyboard built right into the cover makes work easy, the very smart kickstand makes watching a movie or Skyping a friend a delight, the less than a pound-and-a-half weight makes a great alternative to a laptop, and the many other features make it fun for work and play. Now that’s a wowser!”

Microsoft’s surface retails for between £399 and £559, the same price as the cheapest iPad, putting Microsoft into direct competition with Apple. Microsoft will be desperately hoping this latest fiasco doesn’t send consumers into the arms of its competitor.