Dean Smith has been joined at Aston Villa by Richard O'Kelly, who was his assistant at Brentford and Walsall, according to Sky sources.
Smith was appointed Villa's new head coach on Wednesday night, with former Chelsea and England captain John Terry joining as his number two.
O'Kelly has now joined the pair at Villa Park, although it is unclear what role he will fulfil.
Smith had two assistants at Brentford, O'Kelly and Thomas Frank, so it is possible both O'Kelly and Terry will work as his right-hand-men.
Smith made the decision to leave Brentford - who have received compensation from Villa - to join the club he supports, despite the Bees being eight places better off in the Championship.
His first match will be at home to Swansea City a week on Saturday.