Tuilagi has not played for England since their 2014 tour of New Zealand through a combination of long-term injury and suspension and has replaced Saracens full-back Alex Goode in a 24-man party.
Wasps lock Joe Launchbury has shaken off the hamstring injury which sidelined him for England’s 21-10 victory over Ireland last month and comes in for Courtney Lawes, who has been ruled out with an ankle problem.
Saracens second row Maro Itoje, who replaced Launchbury in the squad to face Joe Schmidt’s Ireland, retains his place, while Northampton prop Kieran Brookes has been selected ahead of clubmate Paul Hill.
Exeter hooker Luke Cowan-Dickie has remained with the squad as cover for Jamie George, who suffered an arm injury during yesterday’s training session at Pennyhill Park.
Should England beat Wales and then Scotland dispatch France at Murrayfield 24 hours later, the Red Rose will be crowned Six Nations champions for the first time since 2011 with a round of fixtures to spare.
Victory for England would also avenge their World Cup defeat to an injury-hit Wales in September, although head coach Warren Gatland insists his side will be an even tougher proposition this weekend.
“It was a great performance to get out of that group, but we feel we’re in much better shape now,” said Gatland. “There’s a lot of confidence in the team and we’re treating Saturday as a final.
“It’s going to be one heck of a game and, to be honest, whoever wins on Saturday probably wins the Six Nations.”