US viewers who tuned in to CNN over the weekend for the latest instalment of Anthony Bourdain’s Parts Unknown where in for a bit of a shock when the celebrity chef’s reality show was accidentally replaced by a porn film starring transexual adult star Riley Quinn.

The adult film aired for over 30 minutes, with CNN blaming a local station in Boston, RCN, for the mishap.

In a statement CNN said: “The RCN cable operator in Boston aired inappropriate content for 30 minutes on CNN last night. CNN has asked for an explanation.”

However, the boss of RCN told local media that there was “no evidence” his station was to blame for the raunchy mistake.

Riley Quinn, however, was ecstatic in the free exposure and thanked CNN for the free airtime.

Bemused viewers soon took to Twitter with one posting:“I can’t wait until [RCN] wakes up [tomorrow and] realizes that hardcore porn was broadcast on [CNN] instead of [Parts Unknown] tonight” while another added: “Did anyone else with RCN in Boston see the hardcore porn that was broadcast by CNN by mistake?”