Comedian Phil Zimmerman has hit the headlines for all the wrong reasons – after lunging at Britain's Got Talent judge Amanda Holden.

The stand-up – whose act involves strutting and squawking around the stage impersonating a giant pigeon – was grabbed by security guards he leapt towards the pregnant actress after he was buzzed offstage this week.

One member of the audience in London’s Hammersmith Apollo explained that Zimmerman reacted badly after being roundly booed by the audience during his routine,.

Posting on the Digital Spy website, they said: ‘There was really freaky man who was trying to be funny but he was just weird and scary.

‘When Amanda buzzed him he started acting really scary towards her. She got up out of her chair because she was scared. And then he started coming towards the judges and all the security ran towards the judges' desk... On TV it's going to be so dramatic.’

Another audience member, Katie Beth, said: ‘When the crazy guy was on Amanda looked freaked out and left her seat and spoke to a security guy. Then she went back to her seat only for him to leap off the stage at the end of his “performance”. When he jumped off the stage Amanda was straight back out of her seat and hid behind [fellow judge] Michael McIntrye who spun his chair round. He was hugging her while security grabbed the crazy man.’

Zimmerman, who has been on the open-mic circuit for more than a decade, has today been described as a ‘nut’, a ‘weirdo’ and a ‘barmy wannabe’ by the tabloids following his bizarre appearance. The Daily Mail said he was dressed as a pigeon, although he actually performed in dungarees.

Before being led away, Zimmerman hurled a flyer for his comedy club in Ealing, West London, at the judges, who also included Louis Walsh, standing in for David Hasselhoff.

However, Holden appears not to have been too badly spooked by Zimmerman, posting on Twitter after the audition: ‘‘Been possibly the best day we've ever had in London for BGT today!! Next week, Manchester here we come! X’

Zimmerman’s previous TV credits include Never Mind The Buzzcocks – where he was one of the ‘identity parade’ line-up in 2007.

McIntyre has also had a weird introduction to the show after being mooned at by one of the contestants on his first day in the hotseat.

He got an eyeful from a man whose act involves painting while dressed on in several pairs of underpants, which he removes one at a time to use as makeshift brushes, until he winds up naked.

McIntyre has confessed that he will have to get tougher at judging the hopefuls, saying: ‘I started off being quite nice to the people who weren't very good. But that's all going to change. I find the power very thrilling!’

• Phil has written about his experiences on his own website.