Ozzy Osbourne is halfway through a new album, which will feature guest appearance from Robert Trujillo and Foo Fighters' Taylor Hawkins.

The heavy rocker has reteamed with Andrew Watt, who worked on Ozzy's latest album, Ordinary Man, and the producer tells Guitar World that he and the Black Sabbath star are well on their way to completing the project after he was forced to halt the recording process when he tested positive for Covid-19.

"We're about halfway through," Watt told the publication. "But, you know, it's been hard with Covid and everything to keep him (Ozzy) safe. We all test every day before we work and it's just me, Ozzy and my engineer. So it's taken a little longer this time, but it's cool because the last one was made in this, like, swift love affair of passion, like, 'Oh my God, this is incredible!'

"This time everyone's moving a little slower and we're taking a little more time. And the songs, there's some songs on there that are, like, eight or nine minutes long that are these really crazy journeys. I'm really excited about it."

Watt reveals there's "a bunch" of famous Ozzy fans and friends who will appear on the album.

"I can't say for sure until the end, but I started doing a bunch of basic tracks with Chad (Smith) and Robert Trujillo, who used to play in Ozzy's band. And Taylor Hawkins also came in and played a bunch on the record as well, which adds a different flair.

"I think it's so cool for a rock fan to be able to listen to half an album with Chad Smith on drums, and then you flip it over and you get to hear Taylor Hawkins."

Ozzy has been battling various ailments and injuries in the past two years and his family has been hit hard by the coronavirus in 2020 - his son Jack's daughter contracted the virus at the end of the summer and Sharon Osbourne, Ozzy's wife and manager, is currently in isolation after testing positive for Covid-19.