King admits it'll be difficult to stop his former Spurs teammate.
He told the club's website: "It's a good question, and the answer isn't that simple! We're at home so Sunderland are likely to have less of the ball. As a defender, it's vital you maintain 100 per cent concentration because Jermain is always looking for a goal.
"He's scored a lot of goals in away matches for Sunderland and that will be down to defenders switching off and Jermain will always look to get in behind, looking for any passes through midfield, running in behind. He's always a threat and someone you have to watch for the full 90-plus minutes."