The Black Eyed Peas star Will.i.am carried the Olympic Torch on Monday.
The Voice judge was cheered on by thousands of people as he ran through Taunton carrying the flame.
The United States-born music producer was a surprise addition to the line-up on day three of the relay.
Will.i.am, 37, looked at ease in the warm weather as he jogged through the Somerset town centre.
The Metropolitan Police Torch Security Team, which runs alongside the torchbearer, kept a watchful eye on the cheering crowd.
Before he started running he was passed his mobile phone and was tweeting as he set off down the road under Union Flag bunting and surrounded by screaming fans.
He held his phone in the air indicating to people to follow him on the social networking site.
After a couple minutes he waved to the crowd while smiling broadly.
He also turned around to perform a short moonwalk to the delight of onlookers.
Thousands turned out to watch the torch travel through the town unaware of the surprise appearance.
They waved colourful flags and children held homemade torches made from bright yellow and red paper.
Will.i.am's turn in the relay was over in under five minutes when he passed the flame to the next runner, biathlete Emma Fowler.
'I remember in 1984 the Olympics in Los Angeles, me being a little Will watching it on TV wishing I could be at the Olympic Games.
'I had that flashback when they handed me the torch to run in Taunton
Will.i.am said: 'I'm a huge Olympics fan. I want to see the swimming match, I want to see Usain Bolt.
'I want to see if he's really that fast because I want to race him one day. I wouldn't win but I want to see how close I would come.'
The star said he was amazed at the number of people who had turned the relay through Taunton into a real family occasion.