British daytime series The Jeremy Kyle Show is being probed by Ofcom after a morning edition screened by ITV featured the f-word.
The pre-recorded show containing the bad language was screened earlier this month at 9.25am.
Such strong language would normally be restricted to a post-watershed slot, after 9pm.
A spokesman for the UK's broadcasting regulator, Ofcom, said: “Ofcom is currently investigating the broadcast of offensive language before the watershed in an episode of The Jeremy Kyle Show, on ITV on 4th November.”
The regulator also rapped Channel 5 today for including swearing in shows screened to daytime audiences.
The station was judged to have breached guidelines during the broadcast of three separate programmes, during editions of Big Brother, The Hotel Inspector Returns and It Takes a Thief to Catch a Thief.
A spokesman for the regulator said: “After thorough investigation, Ofcom has found that Channel 5 breached broadcasting rules three times, due to the inclusion of offensive language before the watershed.”