Both horses are trained by Paul Nicholls, for whom Williams works.
In the eventmasters.co.uk Hampton Novices' Chase, Williams will ride Complete Unknown, a seven-year-old who made his chasing debut at Ffos Las under Harry Cobden in late December and secured a neat victory with a fluent round of jumping on soft ground.
The success was a third career win Complete Unknown, whose last triumph was in the EBF Novices' Handicap Hurdle Final at Sandown in March with Williams in the saddle. The pair reunite at Warwick, as Williams' mount steps back up to three miles on ground that will be testing.
"He looked like he'd taken to jumping fences well last time at Ffos Las, having come with a late run. Harry Cobden gave him a great ride," Williams said of the horse's latest outing.
"Three miles is only a positive, he's a horse that relishes difficult conditions like heavy ground. It was soft at Ffos Las over two-miles-five the last day and he did his best work late on.
"He'll love the ground and there's only really positives to come from that Ffos Las run. I've ridden him in the past and I'm looking forward to getting back on him."
The contest has only attracted a field of four, with Dan Skelton's Galia Des Liteaux looking to bounce back after being pulled up in Grade One company at Kempton Park on Boxing Day and Gordon Elliott's The Goffer making the trip over from Ireland.
"The horse of Dan Skelton's didn't jump too well last time out and underperformed, but Complete Unknown has beaten her before over hurdles around Ascot," Williams said.
"Gordon Elliott's runner is a bit interesting, he's had three runs over fences so he's the experienced runner in the field.
"Complete Unknown has got every chance, he's a talented horse and if he puts it all together he should be the one to beat."
Williams has then got a second enviable ride in the Ballymore Leamington Novices' Hurdle, with Knowsley Road looking to maintain his unbeaten record over timber.
The six-year-old was the runner-up on his bumper debut and then won next time out on the level, both times under Williams, after which he graduated to hurdling at the start of the season.
Winning his first start under Cobden, the bay then defied a penalty to prevail again when Williams took the ride in a Chepstow novice in December.
"I've been fortunate enough to have ridden Knowsley a few times in his career, he's a very talented young horse," he said.
"I have always thought a lot of him and he probably shouldn't have been beaten in first time out in his bumper at Exeter but we were still learning a bit about him.
"The bumper wasn't the be all and end all as you can see, he's two from two over hurdles and two-miles-five around Warwick should really suit him.
"He's a lovely, big scopey horse and I don't see him having any problems in the conditions.
"He seems to have taken his races well and only seems to be wanting further. He's stepping up (in trip) and Paul's had this plan with him for a long time.
"When I rode him the last day he was only idling in front, he was hanging to the left but only through greenness. He's a lovely horse who I think a lot of and if he turns up on the day he should also be the one to beat."