The 27-year old has joined the Tigers from West Ham United, signing a three-year deal for an undisclosed fee.
Diame arrived at West Ham from Wigan Athletic in the summer of 2012 and went onto make 79 appearances for the east London club.
"I'm delighted to welcome Mo to the Club," said Bruce.
"His experience, both at international level and in the Barclays Premier League will be invaluable as we look to cement our place in the top-flight."
For breaking stories and all the great banter like us on Facebook: facebook.com/tribalfootball