Ozzy Osbourne is thrilled that his old bass player Robert Trujillo is on his new solo album.

Before he replaced Jason Newsted as Metallica's bassist in 2003, the 57-year-old rocker had a stint touring with the Prince of Darkness in the 1990s.

And Ozzy has hailed Robert for being the only bassist who "did right by him" and not leave him without a replacement when he got the call from the 'Enter Sandman' group.

Robert has reunited with the 'Paranoid' hitmaker and is set to appear on Ozzy's follow-up to 2020's 'Ordinary Man'.

Speaking to the December issue of Metal Hammer magazine, which pays homage to Metallica, Ozzy said: "Rob has always been a great friend of mine.

"He's a great bass player and a great guy; he's the only guy who, when it came time to move, did things the right way.

"I always ask that the guys who play with me, if they get another offer and want to move on, that's fine, just don't drop me in the s***, give me time to get a replacement.

"Rob is the only guy that did right by me for that.

"I'm really happy we've got him playing on the new album as well."

As well as guest spots from the legendary Eric Clapton, Jeff Beck, and his Black Sabbath bandmate Tony Iommi, the heavy metal icon's long-serving guitarist and co-writer, Zakk Wylde, is featured on every track on the hotly-awaited LP.

Responding to 'The Diary of the Madmen – The Ultimate Ozzy' podcast, who asked during a Facebook Live: “Does Zakk play all of the rhythm guitars on the new album?”, Ozzy replied “Yes Zakk plays on the entire new record. He was home from tour this time unlike when I did 'Ordinary Man'.”

The Black Label Society rocker, 54, previously hinted this was the case when he commented on how surreal it is getting to play rhythm guitar for his "heroes".

He teased: “It definitely sounds slamming.

“The same goes for all the guys – what Tony Iommi played, and then Eric Clapton and Jeff Beck, it’s all killer for sure.

“On those tracks I’m playing rhythm guitar for my heroes … it’s crazy! It sounds awesome and I’m beyond honoured to be doing it.”

Zakk hasn't played in full on an Ozzy record since 2007’s 'Black Rain'.

Andrew Watt is producing again and Red Hot Chili Peppers' Chad Smith and Foo Fighters' Taylor Hawkins have also been involved in the new record.