John Bishop practised his 'The Nightly Show' gags in a London pub so that it wouldn't be a flop.

John Bishop

John Bishop

The 50-year-old comedian took over the reins of the new ITV programme from David Walliams this week as a host of celebrities take it in turns to host the show over an eight-week run.

But he took extra measures to ensure the show wouldn't be a bore, after last week's debut run of shows failed to pull in viewers, with its debut rating of 2.8 million dropping to just 1.2 million.

According to the Daily Star, John made a surprise appearance at the Old Rope comedy night in the basement of The Phoenix Pub in London on Monday (07.03.17) to rehearse his jokes.

At just £6-a-ticket, around 60 punters were hoping to see upcoming comedians take to the stage but instead they were treated to a sketch from the Scouser - who usually plays to packed arena crowds with tickets selling for £28-£45 each.

An onlooker said: "He snuck in right after the show started and he was on his own. I couldn't believe it. He looked nervous and told everyone, 'I've got a lot of dog material to try because it's Crufts this week'. He looked a little underwhelmed by the reaction, embarrassed even."

It's understood that John did the gig shortly after the pre-recording of Monday's edition of 'The Nightly Show', which aired at 10pm.

The source added: "I thought 'The Nightly Show' went out live so I was surprised to see him still on stage at 9.50pm!"

And in order to gauge his audience's reactions to his gags, he recorded his performance on his mobile phone.

John's first show on Monday (07.03.17) pulled in 2.4 million viewers.