Take Me Out presenter Paddy McGuinness will also take to the field as part of Robbie Williams's England lineup.
Awake actor Isaacs spoke of his excitement and nervousness ahead of the game in May.
"Having spent most of my youth watching games from the substitute's bench, it's a surreal nightmare to imagine playing alongside some of the world's greatest footballers," said Isaacs.
"However it's such a privilege to be asked to help UNICEF in any way, that my best hope is to take a couple of them out of the game before I'm stretchered off myself. It's for a great cause so how wrong can that be?!"
Soccer Aid 2012 will bring together a host of celebrities and past footballers for a match at Old Trafford on May 27, with Williams and Michael Sheen captaining England and Rest of the World sides, respectively.
Gerard Butler, Will Ferrell and Mike Myers are some of the Hollywood names who will play part of the match, while Edwin Van der Sar, Ruud van Nistelrooy, David Seaman and Teddy Sheringham will be among the legendary footballers.
Olly Murs confirmed his return to the charity event last month after he played the game in 2010.
Tickets are now on sale for Soccer Aid 2012 - call 0161 444 2012 or visit itv.com/socceraid.
> Robbie Williams 'giving up smoking for family, Soccer Aid'
Watch a promo for Soccer Aid 2012 below: