Williams said he was "happy and excited" about the "unique performance" in front of 80,000 fans and many millions all over the world and that it was a boyhood dream.
Federation Internationale de Football Association says it approved a new formula which rewards teams for playing more games, and it takes effect in the post-World Cup ranking on July 19.
"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".
The ceremony will begin half an hour before the game kicks off at 6pm local time (4pm BST).
The Fédération Internationale de Football Association (FIFA) said this year's opening ceremony will have a "slightly different format", focusing on "musical acts and will take place much closer to kick-off". "And, on 15 July, we will find out for whom this precious dream will come true, back on the same stage, after a month-long festival of football in Russian Federation".
Man Utd retract interest in Juventus left-back Alex Sandro
United are believed to be paying over £50m to secure the signature of the player, who was linked with City in the January transfer window.
Federation Internationale de Football Association notes that the new Elo method has been used in other sports for a number of years and is even involved in calculating the women's world rankings, with a specific version (SUM) developed especially to take into account FIFA's considerations.
Trump also assured that the U.S. would hold the tournament "in a similarly open and festive manner" as the 1996 and 2002 Olympic Games that the United States hosted, the Times reported.
However, any positive impact on the Russian economy from the World Cup is likely to be short-lived, according to credit rating agency Moody's, which analyzes the event's influence every four years.
What Liverpool have planned for Xherdan Shaqiri transfer is rather interesting
One name that has been circling around the rumour mill is that of Xherdan Shaqiri. Both Fekir and Klopp are still keen on seeing a move come to fruition.
Read on for a look at what to know ahead of the opening ceremony.
Defeat devices reportedly found in diesel Daimlers
Daimler has previously clashed with the KBA's findings regarding diesel emissions, and has maintained it has done nothing wrong. Daimler hasn't denied the existence of the functions, but have refuted the suggestion that they are illegal.