The Norwich star of Britain's Got Talent says he would never have entered if he'd known the 'ridiculous' reception his performance would get.

But Sam Kelly has no regrets after delivering an audition that silenced a 2,000-strong crowd and has seen social networking sites overrun with positive comments and praise.

His progress could be cut short, however, by a bout of tonsilitis – the Spixworth teenager's 12th in two years – which could leave him singing through the pain in the next round.

He has already had to cancel several gigs, but is adamant the bug won't put him out of the competition.

Speaking to the Evening News yesterday, he reflected on his show-stopping performance on Saturday's Britain's Got Talent series-opener.

He said: 'I don't know what I was thinking when I went for the audition.

'If I had known the attention it would get, I probably wouldn't have done it. I would have been afraid people wouldn't like it.

'Since Saturday it's been ridiculous, but fortunately everyone has been great - I've had 350,000 people watch the video of me, and 6,500 people follow me on Twitter. It's crazy.'

Sam spent 12 hours backstage on the day of his audition listening to the 'brutal' reception for other acts, before he was finally called to perform.

'You could just hear the crowd booing, and how loud the buzzers were – I was thinking 'Oh God, what have I let myself in for?'

'I was too surreal for me to be nervous – it seemed like it wasn't really happening.

'I just gave it the best I could, and when I finished there was just this deafening wall of silence,' he said.

'I thought my trousers had fallen down – I thought I'd done something wrong.'

He said the crowd's reaction – after a stunned silence – was 'completely overwhelming'.

It was a long way from his first gig, at Sprowston Community High School, aged 14, or playing pubs in Brighton for �30 a time as he has been for the past two years.

'At my first ever gig, I think I played Wonderwall by Oasis – standard – and I was rubbish. I was wearing tracksuit bottoms and a gold ring I'd bought from Argos. I think I have moved on since then.'

Sam's choice of song – Bob Dylan's Make You Feel My Love, made famous recently by Adele – was inspired by a wedding he played at two weeks before the audition, a gig he called 'one of my favourite ever memories of playing music'.

He also revealed that minimal practice was the secret behind tender handling of the song.

Sam said: 'I just make sure I'm comfortable with the song: then when you do it for real each line comes out as you feel it. You have to trust in your own feelings.'

While he waits to find out if he has made the live semi-finals, Sam is still dealing with university work and the prospect of becoming a household name – or face, at least.

'When I was in London, there were quite a few gawping faces in the street when people recognised me, which was quite strange.

'But most of the attention is coming through Facebook, Twitter, Youtube, so if I want to get away from it I can just switch off my computer.

'My friends have been really supportive, but they've also made sure I don't get carried away.'

And thoughts of winning will also have to wait, he says, until after the semi-final line-up are confirmed.

'I can't start thinking about that and putting pressure on myself,' said Sam.

'For now, I'm just living in the moment.'