The 71-year-old singer is set to take to his piano to serenade the royal couple - who will tie the knot on Saturday - nearly 21 years after he played 'Candle in the Wind' at the funeral of Harry's mother Princess Diana.
Sources close to the 'Rocket Man' hitmaker told TMZ it is unclear whether he will perform at the church ceremony at St George's Chapel, Windsor Castle, or at their reception, which will be held at St George's Hall.
Elton initially had Las Vegas shows booked for this weekend but he pulled out of them months ago due to a "scheduling conflict".
Just last month, the legendary singer - who attended the wedding of Prince William and Duchess Catherine in April 2011 - admitted he would love to perform for Harry, 33, and Meghan, 36, but claimed he was yet to receive an invite to the nuptials.
He said: "If they asked me to - but I haven't been asked to the wedding yet.
"I would love to be at the wedding to see them because I think they are happy. I know they are so happy."
Elton was good friends with Diana - who tragically passed away in August 1997 aged 36 following a car crash - and he thinks the Princess of Wales would have approved of Harry's bride-to-be.
He recently said: "She would be proud of them. And I am proud of them.
"They are fabulous human beings."
This comes after James Vivian, the director of music at St George's Chapel, recently revealed he had been chosen to lead the musical performances on Harry's wedding day.
He said: "The Choristers, Lay Clerks, Organists and I are very much looking forward to this exciting day and are pleased to be performing at the service music chosen by the couple.
"We are also looking forward to welcoming to St George's musical colleagues from near and far who will be performing at this very special and joyful occasion."
James will direct the Choir of St George's Chapel, which comprises up to 23 boy choristers from St George's School and 12 Lay Clerks, who will sing alto, tenor and bass.
Sheku Kanneh-Mason, a 19-year-old cellist who won BBC Young Musician 2016 and made his BBC Proms debut the following year, will also perform at the royal nuptials.
He said: "I'm so excited and honoured to perform at Prince Harry and Ms. Meghan Markle's wedding. I was bowled over when Ms. Markle called me to ask if I would play during the ceremony, and of course I immediately said yes.
"What a privilege to be able to play the cello at such a wonderful event. I can't wait."