The scrum-half is one of five Cardiff Blues players on the bench as Wales take on England ahead of the summer tour to New Zealand.
He has not stepped onto the turf at the home of English rugby since filling in on the wing and creating a match-winning try against all the odds as Wales claimed a 28-25 victory last September.
Wales were struck by a succession of injuries but the make-shift wing was released down the left and then chipped inside for scrum-half Gareth Davies to score a famous try.
Now with four matches in the Land of the Long White Cloud, Williams is determined to make the most of the opportunity, fingers crossed in his more accustomed position.
He said: “Hopefully I’ll be coming on at scrum-half this time, we have wing covered!
“It’s a big opportunity and every chance you get to put the jersey on is one you want to take. I’m looking forward to it, hopefully I can get on, play well and my part in a win.”
Williams is joined in the match-day squad by Kristian Dacey, Gethin Jenkins, Josh Turnbull and Gareth Anscombe, while Sam Warburton and Tom James will also make the trip to New Zealand.
The 26-year-old reckons an upturn in form for his region has aided his international credentials and he is confident Wales can prosper against the world champion All Blacks.
He added: “I enjoyed this year, especially the second half of the season. Cardiff Blues have been doing well and that’s made my life easier.
“It’s been a tough couple of weeks but that was expected and everyone is mentally and physically prepared for the tour.
“I’m looking forward to going on tour now but obviously there’s England first up, which will be tough.
“We can definitely do well in New Zealand. It’s a good time to go over there to play them. We finished the Six Nations on a high and if we go out there and express ourselves we can create an upset.”