Hull City have appointed Middlesbrough coach Steve Agnew as their new assistant manager.
Agnew has been with Boro since 2007 after spells in the backrooms of Leeds and Hartlepool.
He has now accepted an offer from Bruce to link up with him at the KC Stadium.
"I took a call from Steve Bruce earlier this week and he asked if he could talk to Steve. Aggers has an ambition to work at first-team level and I wouldn't stand in his way," said Boro boss Tony Mowbray.
"We're disappointed because he's a very good coach and he worked extremely hard with a young group last year. It will be a loss to us and yet we wish him well.
"He's a good man and it's a loss to us but a positive for Steve and I'm sure he'll do well."