The Olympic Games is one of the greatest cultural events of the past century. Although in recent decades it has been accompanied by an anthemic song, usually performed by a major star, very few have lasted the test of time. With the exception of Whitney Houston’s spectacular 1988 One Moment In Time, Barcelona remains the most iconic and memorable.

It was created in 1987 to be the theme to the 1992 Summer Games in Barcelona, but Freddie Mercury’s deteriorating health ultimately meant it was only used to accompany a video presentation of the city on the international broadcast.

However, recording the song and performing with his idol, remained one of the happiest and proudest moments of Freddie’s life.

Years later, his PA Peter Freestone told The Express: “After he got Montserrat Caballé to sing with him on the Barcelona album, that was the nearest I’ve seen him to tears. He was so happy. He said, ‘The greatest voice in the world is singing my music.’”

Freddie had already been obsessed with Montserrat’s voice for years. Freestone added: “It was the visit to the Royal Opera House on February 3rd, 1981, for the performance of Un Ballo in Maschera where he (Freddie) heard Montserrat Caballé for the first time.

“It was a pure joy to see the wonderment on Freddie’s face after she had finished singing in the trio during Act I. Freddie just couldn’t believe what he had heard and said then he had just heard the greatest voice in the world.”

Years later, he was asked during an interview on Spanish television who he would most love to sing with. Of course, he answered Montserrat Caballé. Word got back to the opera icon and she put things in motion that lead to their legendary collaboration.

In one of his last-ever recorded interviews, Freddie described his extraordinary joy when Montserrat called him out of the blue.

In 1987 Freddie said: “She just called up a few weeks ago and said she’d love to work with me. I fell flat on the floor. I thought, ‘My God!’ But I’ve loved her for years. I went to Barcelona on a TV show and I said she’s the best singer in the world and I’d love to sing with her and she must have seen it. She called up the office and said she’s like to do things.

“It’s amazing. I’m into opera now. Forget rock n roll. It’s such a challenge, I’ve never thought of writing songs like that. I’m sure the opera critics will slam it but it’s a good challenge at this time in life.”

They met in 1987 and discovered a mutual passion for creating something new. An entire album was born between tapes sent back and forth between the UK and Spain, and recording sessions in London.

Montserrat revealed that Freddie originally came to Barcelona and played her some of his compositions for them to duet on. And she was “captivated.” The opera star said Freddie’s work was “magnificent. It is something very special, it is created from the heart.”

Montserrat’s niece, who shares the same name, remembered the enormous fun and late nights rehearsing in London at Freddie’s West Kensington mansion.

She said: “We were in Freddie’s house, there were days when we were maybe there until six or seven in the morning, because after dinner they went to the piano and he played the piano and sang, and Montserrat improvised. Truly it was an incredible party.

“For Freddie, Montserrat was something out of this world. He had such love and admiration for her, he was always watching to make sure everything was perfect for her. When we arrived at the hotel, there were roses in every room, we wanted for nothing.”

While the pair were still working on their collaboration, Montserrat also gave a performance at the Royal Opera House, with Freddie in attendance.

Freddie described how she “embarrassed” him by introducing him to the crowd: “I was sitting there with my tuxedo and I had to stand up and take a bow. She blew kisses to me and I blew kisses back.”

Montserrat said: “The audience loved it. They went crazy at the Royal Opera House.”

At the official launch of the song Barcelona in Ibiza in May 1987, Freddie joked that he would dedicate the rest of his future to the woman he called Montsi: “(I’ll do) some more songs with Montsi. She’s gonna take up all my time now and I’m quite prepared to do it. I’m looking forward to all that time.”

Of course, time was not something Freddie had. The single was released in October 1987 and became a major hit, reaching Number Eight in the UK charts.

In 1990, Freddie confided in Montsi that his health was failing and that he would not survive to perform their song together at the Olympics.

Montserrat later revealed their emotional conversation: “He said, ‘I won’t make, I won’t make it.’ We were in the recording studio, recording some final things, which was the last thing he recorded, and he said to me, “I can’t do the Barcelona (performance).’

“And I totally stopped and said, ‘Why?’ I thought he didn’t want to. It was true that he had lost a lot of weight and deteriorated a lot and he said, ‘With AIDS, I can’t think about two years from now, anymore.”

In another interview, Montserrat added: “He said, ‘It is my duty to tell you this.’ And I said, ‘No, it is not a duty, but I am very thankful that you told me because it means I have your friendship and this is most important as anything to me.”

The soprano also made a very special personal recording for her friend: “He told me he would have liked to have sung the aria from the Phantom of the Opera and I told him I would record it – and I recorded it in the studio for him.”