The Israeli defender moved to Stamford Bridge in a £5m deal from Bolton in July 2007, but made just 13 appearances for the Blues before he was sold to Manchester City by his now Portsmouth boss Avram Grant.
But the 28-year-old centre back insists relegated Pompey can pull off, arguably, the greatest shock in this famous competition’s history – provided they approach the game with the right mentality.
“In football you do not need to have fear,” Ben-Haim said. “You need a lot of desire and passion to try to do your best. After the game if you come back to the dressing room having done your best, even if it is not good enough we will not be very, very disappointed. But in one game anything can happen.”
He added: “I know all the players, yet even though I trained with them, I don’t think [Frank] Lampard, [Didier] Drogba or [Nicolas] Anelka do the same movements. They are unpredictable. But I have also played against them before so it is not something to get too excited about.”