Salford Red Devils boss Watson is to be joined by the London Broncos' head coach Danny Ward as an assistant to Rugby League Lions head coach Wayne Bennett.
'Watto' was named assistant coach ahead of the return of the Great British Rugby League Lions later this Autumn, this comes as under his tutelage the Devils are currently on a roll in fifth place in the Betfred Super League.
"I was honoured to play so many times for Wales, and I'm delighted that the Great Britain team has been reformed, so it's a privilege to have this chance to be involved on the tour," he said.
"There is a great history of Wales players and coaches being involved with the Rugby League Lions, and I'll also be representing Salford who have given me such a great coaching opportunity."
He will now be involved in assessing players for the selection process throughout the summer before a Great Britain Performance Squad is announced later in September.
Great Britain are set to play in four Tests on consecutive weekends from October 26 til November 16 as they embark on their first tour of the southern hemisphere since the Tri-Nations series thirteen years ago, back in 2006.
Saturday October 26 - v Tonga (Hamilton);
Saturday November 2 - v New Zealand (Eden Park, Auckland)
Saturday November 9 - v New Zealand (Christchurch)
Saturday November 16 - v Papua New Guinea (Port Moresby)
Image: Salford Red Devils