Dubbed the 'Clash of the Legends', Morrison and Brunt will go head to head on Saturday September 24 to raise money for the Albion Foundation.
A number of former Albion favourites have already been confirmed for the game - and now the two managers have been announced.
Mowbray, who left Blackburn Rovers earlier this summer, took charge of 140 games at Albion between 2006 and 2009 - guiding the club to the Championship play offs in his first season.
In his second season he built a side, which included the acquisitions of both Brunt and Morrison, that would go on to win the title.
The following season, despite winning accolades for their style of play, Albion were relegated with Mowbray leaving to take over at Celtic.
He was replaced by former Chelsea legend Di Matteo - who took the Baggies back to the Premier League at the first time of asking.
The following season, despite a handful of good results form dipped and he was sacked midway through the campaign.
Now the pair will return - with West Brom confirming the news on social media by posting a video of Mowbray, who said: "It should be a great day.
"I'm looking forwad to seeing a lot of the lads who played in the team that I managed 15 years ago now. It should be a great day and what will make it better will be a full crowd, I remember the days when we were doing well when we won the league in 2007/2008, and how fantastic The Hawthorns could be when it's bouncing.
"So lets make it a great day and raise a lot of money and I look forward to seeing you all there."
The club have already announced a host of former favourites will play, including Roman Bednar, Peter Odemwingie, Paul Robinson and Jonas Olsson.