Mumford and Sons singer drops cricket F-bomb

How hot is it at the Gabba?

Punters watching the trans-Tasman first Test TV broadcast didn't have to ask after getting a surprise insight into Brisbane's heat thanks to the second F-bomb dropped on the Nine Network's cricket coverage in as many years.

Social media went into meltdown after musician Marcus Mumford let slip the expletive while miked up for The Cricket Show on Saturday.

"It's f***ing hot lads," the Mumford and Sons lead singer could be heard as live coverage returned from an ad break.

Mumford's cussing was clear as the camera lingered over children playing cricket at the Gabba during the Test's day three lunch break.

The cameras then crossed to Mumford who was feeling the heat preparing to face former Australian fast bowler Brett Lee in the Gabba nets as a TV stunt.

Adding to Mumford's discomfort was the fact he had strapped bubble wrap over the top of more traditional cricket protection gear in the clearly baking Brisbane heat.

Some on social media also claimed to hear Mumford saying "w****r" as he battled to stave off Lee.

It comes afte former Australian captain Michael Clarke was caught swearing while verbally jousting with England seamer James Anderson during the 2013 Ashes series.

"Get ready for a broken f***ing arm," Clarke could be heard warning notorious sledger Anderson during the first Test.