Watch: Former IRON MAIDEN Singer PAUL DI'ANNO Plays His First Concert In Seven Years

Former IRON MAIDEN frontman Paul Di'Anno, who has been receiving physiotherapy and lymphatic drainage treatments in Croatia in preparation for his upcoming knee surgery, played his first solo concert in seven years last night (Saturday, May 21) at the Bikers Beer Factory in Zagreb. The show was filmed and parts of it will be included in a documentary about Di'Anno, to be directed by Wes Orshoski, co-director and producer of the acclaimed 2010 film "Lemmy" about the MOTÖRHEAD icon.

The Zagreb concert was free to attend and was held as a way of thanking Paul's fans for their help during the most difficult time of his recovery. The show took place just a day before the IRON MAIDEN's gig at the Zagreb Arena.

Fan-filmed video and photos of last night's show can be found below.

Di'Anno recorded two classic albums with IRON MAIDEN — a self-titled effort in 1980 and "Killers" in 1981 — before being fired and replaced by Bruce Dickinson. He went on to front a number of other bands, including KILLERS and BATTLEZONE, and released several solo records.

Di'Anno recently teamed up with several Croatian musicians to form a new project called WARHORSE. WARHORSE entered the studio to record three songs, two of which — "Stop The War" and "The Doubt Within" — have been released as a special limited-edition DVD single.

A fundraiser for Paul's upcoming surgery has been organized by his friends and fans coordinated by Kastro Pergjoni from the U.K. and Stjepan Juras from Croatia, in collaboration with the other members of WARHORSE. All proceeds from the single will be used to cover the costs of Paul's treatment and related needs.

In February, Di'Anno told the "Još Jedan" podcast that his health was "better" than it was just a couple of months earlier but noted that he still "a lot of work to do — a lot of physio and stuff like that."

Paul went on to blast the U.K.'s free-at-the-point-of-use National Health Service (NHS),saying: "Fucking NHS sucks. I was a defender of them big time. But the nurses are awesome and all the workers. It's the fucking bureaucracy bullshit — the management and the people who run the NHS are just total assholes. But the poor heroes — the nurses and the staff — they're great, but their hands are tied. So they didn't know what to do. They just dumped me."

Di'Anno, who turned 64 on May 17, outlined some of the recent health issues he has battled that have kept him from performing for seven years.

"I caught sepsis [when an infection you already have triggers a chain reaction throughout your body] in 2015, and it almost killed me," he said. "And I spent eight months in a hospital in England. You've got a crucial 45 minutes to get as many antibiotics in you before you die, and they managed to do that, which was great. Then I spent eight months in a hospital, and then another three months in a care home. And while I was in there getting things done, on hospital visits, I caught MRSA [Methicillin-resistant Staphylococcus aureus, an infection caused by a type of staph bacteria that's become resistant to many of the antibiotics used to treat ordinary staph infections] there twice, in the hospital. So that was it. So it kept delaying things and delaying things… And then they took this knee out put this cement thing in. And it was only supposed to be in there for a year. And the first time they put that in, it broke, so they cut me open again and put another in. And that one is still in here. And while it's been in there this long, it's going toxic. So, what the fuck are they doing over there at the NHS?"

Di'Anno reportedly underwent an operation in 2016 to remove a "rugby ball-sized abscess" on his lungs and required a knee-replacement operation on both knees after getting involved in several motorcycle accidents over the years.