Ozzy Osbourne is suffering "badly" from ADHD.

The 76-year-old rock icon is set to reunite with Black Sabbath on 5 July in Birmingham for the 'Back to the Beginning' concert, which is set to be his final show after he was struck by a series of health issues, and he has now admitted the impact of preparing for the gig.

He told the 'Ozzy Speaks' podcast on SiriusXM: "All I can say is I'm giving 120 percent. If my God wants me to do the show, I'll do it."

The performance at Villa Park marks Ozzy's first live appearance since 2018 and follows a series of health setbacks, including his 2020 public disclosure of a Parkinson's disease diagnosis.

He added on his podcast about the mental toll of preparing to return to the stage: "My head's crazy. ADHD - I have that badly. I will have done the show and died a death before I even started my exercises.

"So I try and put it on the back burner. I'm not going up there saying, 'It's going to be great. I'm really confident.'"

Ozzy recalled a specific instance of intense fear before a previous show, saying: "I remember being in fing Vegas one time being in the dressing room going, 'I'm going to play. I'm going to die'.

And I talked myself into blowing the gig. It was only two f-ing songs."

Referring to his wife, he added: "Sharon goes, 'Just don't think about it.' I obsess about a f-ing bird c******* on my show."

His wife, Sharon Osbourne, 71, has spoken candidly about his condition.

Speaking to The Sun, she said: "He's very happy to be coming back and very emotional about this. Parkinson's is a progressive disease… it's affected his legs. But his voice is as good as it's ever been."

Ozzy's preparation for the show includes rigorous training.

He said: "I have got this trainer guy who helps people get back to normal. It's hard going, but he's convinced that he can pull it off for me.

"I am having my blood pressure taken 15 times a day. I've got this f***ing device on my finger. It's a monitor to say how my heart rate is."

Ozzy also admitted he is still uncertain whether he will perform standing up or seated, following multiple spinal surgeries related to a 2003 quad bike accident at his Buckinghamshire home.

A fall in 2019 displaced metal rods inserted into his back from the crash, which he said has caused more complications than Parkinson's itself.

Ozzy was diagnosed with a mild form of Parkinson's in 2003 and delayed going public with his news until 2020.