The 78-year-old musician, nicknamed the Godfather Of Heavy Metal, co-founded the rock group in the 1960s alongside the late Ozzy Osbourne, Terence “Geezer” Butler and Bill Ward.
Black Sabbath’s final show at the Back To The Beginning concert in Birmingham in July last year was made into a movie which will hit screens in October.
Asked whether he thought the film’s release would be emotional, Iommi said: “Yeah, I do yeah. I mean I’ve watched the footage and it’s emotional. I’ve watched it only twice now.
“I find it difficult to watch it, to be honest, because obviously (of) our relationship with each other. But I’m sure people will like it.”
Osbourne died of a reported heart attack aged 76, just over two weeks after the farewell concert.
He had suffered from a string of health issues over the years including multiple surgeries following a fall and being diagnosed with Parkinson’s disease.
Iommi added: “It’s been up and down for me” since Osbourne’s death, adding: “I’ve just kept busy, really.
“I’ve just kept busy, really, you know, I can do nothing else.
“I do what I do, and it’s been up and down for me.
“Obviously, the Sabbath thing has finished, but it’s enabled me to do other things, other ventures, and I played on Robbie Williams’s last album.”
The guitarist paired with Williams for the rock song Rocket, released in May last year.
Iommi was made a Member of the Order of the British Empire by the Princess Royal at Windsor Castle on Wednesday for services to music and charity.
Asked about how he felt about the honour, he said: “Brilliant. Really, it’s really going.
“I mean, I’ve got a lot of awards over the years… but this is very special to me because (it is) from our own country, from England, so yeah really great.”
He added Osbourne, known as the Prince of Darkness, “would have been pleased” with him receiving the honour.
Born in Birmingham in 1948, Iommi almost did not pursue a career in music after being told he may never play again when he lost the tips of two fingers on his right hand during an industrial accident.
But he later met drummer Ward and, in 1968, the pair formed a heavy blues rock band based in Birmingham – enlisting bassist Butler and frontman Osbourne to form what was then called Earth Blues Company.
The group later changed their name to Black Sabbath, and went on to sell millions of records over the next decade with tracks including Paranoid and War Pigs.
Black Sabbath had many different line-ups throughout the years and achieved two UK number one albums, won four Grammy Awards and were inducted into the Rock And Roll Hall Of Fame.
While the band is widely hailed as a pioneer of the heavy metal genre, Iommi added: “it was difficult to get through” at the start, as the band “came up with something completely different”.
He said: “We came up with something completely different in those days, which was really difficult to get through, but the whole thing is belief, believing in what you do, and we love what we’ve done.
“And it took a lot of work because there was no internet then, and no websites and all the rest of the stuff.
“You had to physically go around all these places and play, different countries and word of mouth, so that was sort of how you had to do it then.
“But yeah, I mean, I didn’t know to this day now that we were as big as ever.”
Iommi has also dedicated himself to humanitarian projects and advocated for charities including Macmillan Cancer Support, having been diagnosed with lymphoma a few years before revealing he was in remission in 2016.
Earlier this year, the star said he had auctioned one of his guitars and raised £53,000 for a new haematology and oncology centre at the Birmingham-based Heartlands Hospital Charity.
Iommi said: “I love doing the charities, and it’s very close to my heart because I was diagnosed in 2011.”
Talking about the auction, he added: “I enjoyed doing that. It’s nice to give back because I know what it’s like for those patients, and they needed new machinery and new beds, and it was great to be involved, to be able to do that and help to buy the new stuff.”
The guitarist said he was pleased with the release of his new solo album, From the Dark, on October 23, adding he was “looking forward to that coming out”.
