Wales will be led by Lydiate as they take on Georgia this weekend in Cardiff in a historical first ever test between the two nations.
Wales have made 14 changes to their side that lost against Australia last week with only Williams a survivor from last week.
Williams switches to full-back, from wing, in a new-look back three alongside Alex Cuthbert and Hallam Amos.
In the midfield Owen Watkin, who made his debut last Saturday, partners Scott Williams with Rhys Webb alongside Rhys Priestland as the starting half-backs.
In the pack Leon Brown, who made his international bow against Australia, lines up alongside Nicky Smith and Kristian Dacey in the front row.
Cory Hill and Adam Beard make up the second row with Lydiate packing down in a back row alongside Sam Cross at openside flank and Seb Davies at number eight.
“We felt this week was really important to give a number of the squad as much exposure as possible to Test match rugby,” said Wales head coach Warren Gatland.
“It is an exciting opportunity for some of the younger guys to take the field and show us what they are capable of.
“We have got a fair amount of experience to throw into the mix too, both with players who have got a decent number of cap numbers but also players who have been around this environment for a good while too.
“Georgia are coming to Cardiff on the back of a good victory last weekend and they will be looking to show what they can do on this stage and we have to be ready for that.”
On the bench uncapped Dragons hooker Elliot Dee features in Wales’ matchday squad for the first time with Wyn Jones and Tomas Francis the other front row replacements.
Josh Navidi and Taulupe Faleatu complete the forward contingent. Aled Davies, Dan Biggar and Owen Williams provide the back-line cover.
Wales: 15 Liam Williams, 14 Alex Cuthbert, 13 Scott Williams, 12 Owen Watkin, 11 Hallam Amos, 10 Rhys Priestland, 9 Rhys Webb, 8 Seb Davies, 7 Sam Cross, 6 Dan Lydiate (c), 5 Cory Hill, 4 Adam Beard, 3 Leon Brown, 2 Kristian Dacey, 1 Nicky Smith
Replacements: 16 Elliot Dee, 17 Wyn Jones, 18 Tomas Francis, 19 Josh Navidi, 20 Taulupe Faletau, 21 Aled Davies, 22 Dan Biggar, 23 Owen Williams
Date: Saturday, November 18
Venue: Principality Stadium, Cardiff
Referee: Mathieu Raynal (France)
Assistant referees: Shuhei Kubo (Japan), Sean Gallagher (Ireland)
TMO: Leo Colgan (Ireland)