Chris Evans' breakfast radio show is being investigated by Ofcom after actor Jeremy Irons swore on the show.
The media watchdog confirmed they are looking into whether or not Irons' use of a swear word breached rules regarding offensive language.
"Ofcom is investigating this programme, which included the most offensive language before the watershed," they confirmed.
Irons appeared as a guest on the BBC Radio 2 show in March.
While recounting a story about fellow actor John Hurt, he accidentally used the word f***** on air.
Both Chris and Jeremy apologised immediately following the incident.
BT Sport's Football Tonight is facing a similar investigation after the words f*** and f****** were broadcast in a Saturday morning repeat of the programme.
ITV's flagship talent show, Britain's Got Talent, will not face any further investigation after viewers complained about a sword swallowing act.
During the first episode of the show viewers watched as he passed a sword through his mouth.
The 26-year-old from Moldova performed what was described as "one of the most dangerous acts ever" on the ITV show.
Ofcom said it had assessed a number of complaints but would not be investigating the matter further.
It said: "The repeated warnings and clear references to the inherent danger of the act meant it was very unlikely that audiences would attempt to copy it. Also we found the content was in line with audience expectations."
Complaints from viewers had centred around fears that children may have tried to copy or perform the act themselves.