The 61-year-old left the Andalusian club in May before replacing the Ernesto Valverde as the haed coach of the Catalan club in January.
The Betis exit came after a spell of poor form saw the club finish tenth place in the La Liga table, even though the club has fared little better this season and head into Sunday's clash 13th.
In his pre-match press conference Setien said: "It's a special game for me and my staff. We spent two extraordinary years there and it is true that the match has some special connotations. "We know the team well and, although new important players have arrived, we have quite a deep knowledge of these players."But that doesn't mean that we'll have them under control. We know that it will be a difficult game. Their last results have not been what they wanted, but against Real Sociedad they played a great game."
Barcelona sit second in the La Liga under Setien's leadership, but saw their Copa del Rey campaign come to an end on Thursday after a 1-0 defeat to Athletic Bilbao. Source- Daily Mail