A spokeswoman for football's world governing body said: "We are extremely happy to have been able to gather such a high-level line-up of artists for the opening ceremony, which for the first time and for the benefit of the fans in the stadium and watching on TV will take place just half an hour before kick-off and will focus on musical performances".
Hosts Russia get things underway in two days' time when they take on Saudi Arabia at the Luzhniki Stadium.
Williams will be joined by Russian soprano Aida Garifullina, and - presumably not on vocals - former Brazilian global Ronaldo, who was in the winning team in 1994 and 2002, The Guardian reported.
He added: "We'd like to invite football and music fans to party with us in Russian Federation, in the stadium, or to tune in their TVs a little earlier for an unforgettable show".
Stephen Doughty, a Labour Member of Parliament on the Home Affairs Committee exploring suspicious deaths of Russians on British soil, claimed it is "surprising and disappointing" that Williams had "agreed to be paid by Russia and FIFA".
"Uruguay have lots of big-game experience and they will be looking to Luis Suarez to provide some star quality to go with it", he added.
Read on for a look at what to know ahead of the opening ceremony.
"I never imagined I would be part of this huge celebration, the World Cup, happening in my own country", the soloist from the Vienna State Opera said.
"The image that I will be presenting to the whole world will be very symbolic and associated with a dream coming to life".
Here is an XI of the stars heading to Russian Federation this summer who received the highest average ratings across the season.