Were Xtina, Rihanna performances too racy?

British TV watchdog officials have officially launched a formal investigation to determine whether racy performances by Christina Aguilera and Rihanna on reality show The X Factor were too risque for its family audience.

The pop stars were invited to appear on the grand final of Simon Cowell's U.K. talent show on Dec. 11 to collaborate with two of the remaining contestants.After their duets, both singers took the stage to belt out their own songs, but their saucy routines left viewers at home furious - and media regulators at the U.K.'s Office of Communications (Ofcom) were bombarded with more than 2,750 complaints by those angry the performances were allowed to be shown before the 9 p.m. watershed.

The public outcry has now prompted Ofcom executives to look into claims Aguilera and Rihanna's appearances violated the Broadcasting Code, which states that "children must be protected by appropriate scheduling from material that is unsuitable for them."

The confirmation of the Ofcom investigation on Sunday comes days after British politicians criticized watchdog bosses for failing to take swift action over the complaints.

Aguilera has already defended her sexy moves, which saw her cavort around the stage with a group of female dancers, as she performed a track from her new movie musical Burlesque.

She said, "I don't think there is such a thing as too raunchy when it comes to the art form of burlesque. It's very empowering to women to feel confident in their own skin and in their bodies and this represents that.