Ace Bhatti, of Whitby, and a friend were students at a theatre in London which backed on to Mercury’s home and they decided, one Christmas, to perform outside the property for the singer.
“I had started to pay the guitar, knew about three chords, and me and a friend who were huge Queen fans, said ‘let’s go to Freddie’s house, do some carols and try to mix them with Queen songs,” said Bhatti, 49.
“There was a big wall, and on the wall was a door with a camera on.
“We knocked on the door and the camera popped out and we started singing Queen songs interspersed with Christmas songs. We were terrible.
“We heard heavy footsteps and the biggest man I have ever seen stood there; he was so tall, only slivers of light came out of his shoulders. I thought at this point he was going to knock me out.
“He smiled really nicely and said ‘Freddie likes your singing, boys, here’s a tenner each.
“In my head, when we did it I thought we would get invited in, it was stupid.”
Unfortunately, Mercury was extremely poorly at the time as he battled AIDS and he died a year later, in 1991 - now, a generation on, Bhatti is playing the singer’s father, Bomi Bulsara. And it is a relationship even diehard fans would know little about.
“The role, really, is to reveal Freddie’s history, where he came from and the fact that he was chased out of Zanzibar,” said Bhatti, who hailed Mercury as an exceptional talent.
“Most people don’t know that about him,” he said.
“There’s the initial thing of breaking away from his family; I don’t want to give too much away but hopefully we will see some sort of reconciliation. No-one would fully know the story of Freddie and his father.
“What I had to go on was photos and stuff people had written, and the script, and from there we built the character.”
Mercury was born Farrokh Bulsara, of Parsi descent, before moving to England with his family in his late teens.
Bhatti sees the film as “the ultimate immigration story.”
Growing up as part of a working class family in the 70s, when racism was rife, Bhatti said there were two people he looked up to - Pakistani cricketer Imran Khan - and Mercury.
“If you want young Asian men to be part of society, you need good strong role models,” he said.
“What shocks me even today is that people say ‘I didn’t realise he was Asian as he kept it so well hidden.
“It’s been fantastic for me to be able to show that this is what he really was and where he came from.
“I see the film as the ultimate immigration story.”
Bhatti fears the likes of the charismatic star won’t be seen again.
“What makes me feel slightly sad is that I’m not sure these [types of stars] will ever go on again as we live in an era of Simon Cowells and the X-Factor and not someone struggling to earn their stripes.”
Bhatti, who played the public prosecutor in the TV drama series Three Girls as well as evil Dr Yusef Khan in EastEdners, was full of praise for co-star Rami Malek, who plays Mercury in Bohemian Rhapsody.
“It was great being in a scene with him and when someone does it well, it’s great to see.
“He is a lovely man.”