Famed actor and game contributor, Declan Mulvey, recently wrote on his CV that he was involved in the devlopment of Grand Theft Auto V. Many have taken this as proof of a new GTA but, discretion would be the better part of valour in this instance as, it turns out that it was just a typo.
As excited as everyone was getting about the idea of a GTA V, people will just have to cool their guns for now. Patience is always a virtue.
Thanks to CVG for the info.