But this weekend's clash against Argentina at the Millennium Stadium will be his first start and he is looking to put in a big performance against the side who finished third in the 2007 World Cup.
"This is going to be my first start and I'm so looking forward to it," said Knoyle.
"It is a great honour. I have worked really hard and we have all been grafting to get to this point.
"You have to keep working hard, doing the extras and wait for your chance but now I have that opportunity.
"I wouldn't have believed this time last year that I could have the opportunity of going to a World Cup.
"But I have to take what I can and make the most of being in this camp among some great professionals.
"We need to go out all guns blazing against Argentina. There are a few boys, including myself, who have points to prove.
"You have just got to go out there and give it all you have got.
"I need to do my bit and try and give the coach a bad head before he picks the squad."
Tickets are still available for the game priced at £20 for adults and £15 for under 18s are available at the WRU website or by calling the ticket hotlines 08442 777 888 or 02920 230130.
The buy one get one free offer applies across all ticket prices and ticketing outlets. Fans can visit www.wru.co.uk/tickets for more information.