Northampton have won the past 10 meetings between the teams, with the most recent victory coming in the form of a 74-13 Aviva Premiership thumping at Franklin’s Gardens in May.
But Dai Young’s side showed they will be a force to be reckoned with this season as they opened up with a last-gasp 34-28 defeat to Saracens at Twickenham last weekend.
And Saints attack coach King, who spent 10 years as a player at Wasps, racking up 1,000 points in the process, knows his old club will pose a big threat this weekend.
“They had a tough finish to their game against Saracens last weekend and it will be a difficult game because they’re a team that is certainly on the up,” said the former England fly-half.
“They’ve recruited well, they’re well coached, they’ve got dangerous players all over the field and we need to make sure we’re switched on for the full 80.”
King believes the appointment of England flanker James Haskell as captain is an inspired choice by Wasps.
And he recognises the ability they can boast across the park, with Saints ready for another tight Adams Park tussle.
“They’ve made James Haskell captain and he’s a player I know very well,” said King, who helped steer Saints to a dramatic late 17-15 win in High Wycombe last season. “James is a good leader, he leads from the front.
“They’ve got some real X factor players, a good set of forwards, experienced half-backs in (Joe) Simpson and (Andy) Goode so they’re a strong team.
“They’ve also got Tom Varndell, Elliot Daly and a couple of big Samoan wingers (Sailosi Tagicakibau and Alapati Leiua) they’ve signed as well.
“They’ve got some proper players coupled with some good young English players and they will be a handful this Sunday.”