Adam Lambert previously performed with Brian May of Queen during Fire Fight Australia in Sydney, Australia. Photo / Getty Images
Queen and Adam Lambert are set to open the BBC's Platinum Party At The Palace concert.
In honour of the Queen's 70-year reign on the British throne, the Platinum Jubilee concert will see Brian May, Roger Taylor and Adam Lambert perform at Buckingham Palace on June 4.
The performance comes 20 years after guitar god May, 74, performed God Save the Queen from the rooftop of the same royal residence for the British monarch's Golden Jubilee in 2002.
The We Are The Champions hitmaker said: "Twenty years after playing the Queen's glorious golden jubilee, we're very happy to be invited again. Then there was a moment when I wondered … after Buckingham Palace roof, where can you go? Well … you will see."
Diana Ross was reported to have joined the bill and that's now confirmed.
The Motown legend said: "I have had the honour of meeting the Queen many times throughout my life, including when I was with my family.
"Her Majesty has and continues to be such an incredible inspiration to so many across the world and I was absolutely delighted to receive an invitation to perform on such a momentous and historic occasion."
Other performers confirmed for the star-studded concert include the UK's Eurovision finalist Sam Ryder, Duran Duran, Bond theme composer Hans Zimmer, Alicia Keys, Nile Rodgers and Andrea Bocelli.
Plus, Ella Eyre, Craig David, Mabel, Elbow and George Ezra.
Sir Elton John has pre-recorded a performance for the special event.
With a duration of two-and-a-half hours, there will also be special appearances from the likes of Sir David Attenborough, Dame Julie Andrews, Stephen Fry, tennis ace Emma Raducanu and football legend David Beckham.
The Royal Ballet and Britain's Got Talent dance troupe Diversity are also on the bill. The event - which will be watched by 22,000 live - will take viewers and attendees on a journey through fashion, sport, the environment, pop music and musicals over the past seven decades.
Andrew Lloyd Webber has curated the musicals segment and Hamilton creator Lin-Manuel Miranda, and the casts of The Phantom of the Opera, Six, The Lion King and Joseph and the Amazing Technicolor Dreamcoat will be featured.