Audiences were surprised the Bradford teenager had such a powerful singing voice after struggling to even introduce himself to the judges during the opening heats.
The 17-year-old has been blighted by a severe stutter since he was young and despite intensive therapy he still has enormous trouble with public speaking.
But this has endeared him to audiences further because of his bravery in putting himself through such a public contest, knowing he may not be able to speak at crucial moments.
His biggest setback was appearing at the first Pop Idol press conference and not being able to answer questions from journalists.
But amazingly the stutter disappears as soon as he opens his mouth to sing.
Gareth has not been afraid to show his emotion on live television.
He memorably cried when his closest friend from the show Zoe Birkett was voted off, sparking rumours they were in a relationship.
It was his tear-stained face that adorned the front pages the next day, rather than that of the defeated Zoe.
And Gareth has shared the hard work of trying to overcome his stutter with viewers.
Choirboy
He has admitted the rollercoaster that has been Pop Idol has got the way of his therapy, making him slip back into old habits.
The judges have constantly commented Gareth has what it takes to go all the way, with both his voice and look.
His own idol is Robbie Williams, although Britney Spears wins his vote for best looking star.
Gareth is a former choirboy who once sang for the Queen at Bradford Cathedral.
He has had several cracks at telly talent searches, appearing on Steps II the Stars and Michael Barrymore's My Kind of Music.
He is keen to tell people he is not just a pretty pop face and spends his spare time writing his own material.
The singer comes from a large family with three younger sisters as well as three foster siblings.
Screaming girls
He is studying for his A-Levels in Bradford, although it is unlikely he will complete his education if he wins a recording contract through the show.
He says that apart from his love of singing, he would love to be famous so he could help other people and donate money to charity.
As part of his pledge to Pop Idol voters, Gareth has promised not to let fame go to his head, despite adoring girls already screaming his name whenever he is out.
His shy and sensitive manner, along with boy band good looks could be enough to keep him in the lead.