The opening ceremony will be held on Thursday at Moscow's 81,000-seat Luzhniki Stadium and will kick off at 5:30 p.m. local time [2:30 p.m. GMT], half an hour before the opening game between Russia and Saudi Arabia.
"I'm so happy and excited to be going back to Russia for such a unique performance. I've done a lot in my career, and opening the FIFA World Cup to 80,000 football fans in the stadium and many millions all over the world is a boyhood dream," Williams said as quoted by FIFA's official website.
Vienna State Opera soloist Garifullina stated that she never thought she would be a part of such a huge football event happening in her own country.
The World Cup will be held in a total of 11 Russian cities from June 14 to July 15.