Channel 4 is being probed by the media watchdog after a lewd comment made by comic David Walliams on one of its shows sparked a number of complaints.
Ofcom said it is "assessing" if the joke, in which the Little Britain star said he would like to perform a sexual act on a teenage member of boy band One Direction, had breached the broadcasting code.
Walliams, 40, who has written a number of children's books, was appearing on Chris Moyles's Quiz Night at the end of last month when he made the sexual remark to the Radio 1 DJ.
During the show, which was aired an hour after the watershed at 10pm, David agreed with Chris that he liked 17-year-old singer Harry Styles "because of his hair", before adding the lewd remark.
According to The Sunday Times, Channel 4 received four complaints from viewers, while Ofcom received two.
An Ofcom spokesman said: "We will assess the complaints against the Broadcasting Code, the rule book of standards which broadcasters must adhere to."
Channel 4 said the show was aired post-watershed and that viewers had been warned of strong language and adult humour.