The former Manly Sea Eagles star braved the Storm on many occasions during his time in the NRL and knows a thing or two about what to expect on Sunday.
"Melbourne Storm is a remarkable success story; they won the NRL in their second year in the competition which I think says it all" said Williamson.
"Preparing for a game against Melbourne Storm, you always know you're in for an exciting game against quality opposition. They have fantastic players right across the park, so you have to be on your game, otherwise they will exploit you."
As well as lining up against many of the current Storm squad, Williamson also has admired many of them who turn out for his national side, Australia.
Williamson was in the Manly side that suffered a 40-0 defeat to Melbourne in the 2007 NRL Grand Final. Although Manly got their revenge in the 2008 Grand Final, Williamson missed the rematch through injury. However, Williamson insists he has no unfinished business with Melbourne.
"Revenge is the last thing on my mind; that was then and this is now. I'm just looking forward to a competitive game, a great afternoon and a performance we can build upon for the rest of the season."
Tickets for Harlequins v Melbourne are available now for just