The acclaimed playback singers, who performed at the Royal Albert Hall last year, will be paying their personal tribute to legendary singers Mohammed Rafi, Lata Mangeshkar, Talat Aziz and Noor Jahan.
Speaking at a recent press conference, Sonali said: "This is truly a once in a lifetime opportunity to perform our favourite childhood numbers from our favourite childhood singers who we idolised. It's a wonderful opportunity and thanks to Saregama and our London audience for having us back with this unique concept."
Speaking to Digital Spy, Roop Kumar explained why he chose to pay tribute to the four world-renowned singers and what makes them legends.
"Look at the contribution of their work in the music industry," he explained. "Indian music marks every stage of life, the day you are born, the song your mother sang to you as a baby, the music of your youth, or your old age. In your darkest moments the voice of Mohammed Rafi was a support to you, Lataji was like a sister, Noor Jahan a friend or Talat Aziz like a guru.
"We have lived every day of our lives with their music, their voices. They have given us so much that we must honour them. Today's singers come and go, but they have ruled Indian cinema for 50 years. That's why they are legends. We need your blessings and support for the celebration of legends."
Known as the voice of Shah Rukh Khan, Roop Kumar is famed for recording songs such as 'Rab Ne Bana Di Jodi', 'Sandese Aate Hain' from the film Border and 'Maula Mere Maula'.
He explained why he feels Bollywood music appears to resonate with the British audience so much.
"We were here with Saregama before at the Royal Festival Hall for a sold out show and the response was overwhelming," he commented.
"In London the audience is so receptive because they miss their culture. You're all so far away from your village, from your homeland, that when someone comes here with the spirit of India, those same sentiments are awakened. When I sing the song 'Ghar Khab Aoge', everybody was in tears and even I started crying."
Amarpal Gaind, Head of Operations for Europe at Saregama, explained why he felt Roop Kumar and Sonali Rathod were the ideal singers to pay tribute to the legends of Indian cinema.
"Planning and executing a tribute concert is never easy. You are working with voices that have been heard over 50 or 60 years. That is the legacy of these artists," he said.
"We have selected two such fine artists to pay this tribute. They are classically trained and have had a lot of commercial success in their own careers. They have versatility. They have been scoring hit after hit not only in playback singing in Bollywood but also in different genres of Indian music, ghazals, folk music and in sufi music also. It's a great pleasure to have them with us to play part in such as wonderful series of concerts."
Describing the importance of music in their life, Rathod said: "Music is my sustaining power. If I'm upset music clams me down; if I'm very happy then music increases the sense of joy. At every point music is my support."
Roop Kumar explained that for him, music is life: "I think for me music isn't any other activity that I am doing. It's like I'm breathing or my heart is music. Music is me."
'Celebrating the Legends' with Roop Kumar & Sunali Rathod will take place at Birmingham Symphony Hall on Wednesday, September 5; De Montfort Hall in Leicester on Friday, September 7; and London's Hammersmith Apollo on Saturday, September 8.