The Stuttgart midfielder had been linked with a move to the newly-promoted Premier League side with talks progressing well last week. With all parties now agreeing to the transfer, it’s reported that the deal will see Forest pay around €15m for the Belgian.
The 24-year-old is expected to complete his medical in Nottingham today before being announced as their latest signing in a window that has seen them spend heavily on new recruits.
When Mangala puts pen to paper, he will become the fourth Bundesliga player to move to Forest this summer.
So far this transfer window, the newly-promoted Premier League side has signed Omar Richards from Bayern Munich, Taiwo Awoniyi from Union Berlin, and Moussa Niakhaté from Mainz.
With such high-profile signings, many believe that Forest could avoid the drop in the upcoming Premier League season.