Last year's X Factor final featuring Christina Aguilera and her backing dancers in a racy routine was "at the very margin of acceptability", broadcasting watchdog Ofcom has ruled.
The "sexualised" pre-watershed scenes, aired in December on ITV1 at the end of the seventh series, sparked 2,868 complaints to the media regulator.
US singer Aguilera donned a short black dress while her female dancers, who were bent over chairs, wore suspenders, bra tops, fishnet stockings and basques in the raunchy routine.
Ofcom said that over one million young children were watching the live final, and 50,000 saw the repeat the following morning.
It stated that Rihanna's performance on the same night, where she removed a wraparound dress to parade on stage in a bikini, was not inappropriate for the time when it was broadcast.
But it said that Aguilera's burlesque-style routine "was at the very margin of acceptability for broadcast before the 9pm watershed and especially" when it was repeated at 9.30am the next day.
It has now asked ITV to attend a meeting on the issue. As a result of the broadcast, Ofcom also wants broadcasters who intend to transmit similar material to meet the watchdog to discuss whether it complies with the broadcasting code.
Viewers complained that the material should not have been on "a family show", and that the raunchy content was "too sexually explicit and inappropriate for the young audience".
But ITV said that burlesque routines had become "almost mainstream" and that it had used certain camera angles and wide shots to minimise potential offence following rehearsals.
Ofcom said The X Factor, which featured Simon Cowell, Louis Walsh, Cheryl Cole and Dannii Minogue on last year's judging panel, was a family show, which has "consistently attracted a significant child audience".
It stated that the controversial scenes were not in breach of the broadcasting code.
But the watchdog said that "broadcasters of programmes that attract family audiences...should recognise the potential for causing offence" before the watershed with scenes "which contain clear sexual overtones".
"In these circumstances, broadcasters must take great care to provide appropriate protection for those audiences," it added.
The watchdog is set to issue new guidance "about the acceptability of material in pre-watershed programmes that attract large family viewing audiences."
It concluded that "there was editorial justification for the type of costumes that the dancers were wearing, and the style of the dance routine overall.
"However the overtly sexual nature of the burlesque-style routine of the dancers was... nevertheless clearly capable of causing offence to some viewers and we considered that this content was at the very margin of acceptability for broadcast before the 9pm watershed, and especially when broadcast on December 12 at 9.30am."
Ofcom also said that photographs of the performances published in a national daily newspaper which it does not name were "significantly more graphic and close-up than the material that had been broadcast in the programme, and had been taken from a different angle to the television cameras" leaving readers with "the impression that the programme contained significantly more graphic material than had actually been broadcast".