They stole the half-time show at The Super Bowl at the weekend but Red Hot Chili Peppers have been accused of playing without their guitars plugged in for their song with Bruno Mars.

The band joined Mars for a rendition of Give It Away but some musicians have suggested that bassist Flea and guitarist Josh Klinghoffer were actually playing inaudible instruments.

Living Colour guitarist Vernon Reid tweeted: "That guitar is plugged into NOTHING."

"Flea . . . I mean we all know, but for god's sake at least try to humor the children," added blues guitarist Joe Bonamassa, who noted that Flea's bass and Klinghoffer's guitar lacked trailing cables and wireless packs.

However, as Reid himself and others have pointed out, it's not unusual for giant televised performances to use pre-recorded music.

"They leave NOTHING to chance," he wrote, adding that wireless packs "would be a nightmare given the huge amount of wireless channels [in use]".

The Chilis and Mars' performance attracted the largest audience in the history of the Super Bowl.

According to Billboard, the show pulled in 115.3 million viewers, beating the 114 million record set by Madonna, M.I.A and Nicki Minaj in 2012 and the 110.8 million who watched Beyonce in 2013.