Metallica announced last week that it was canceling its upcoming tour of Australia and New Zealand so Hetfield could go back to rehab.
"My best out to James Hetfield," Iommi wrote in a Facebook post, along with a photo from the '90s of himself and Hetfield. "You've done the right thing seeking help — I'm thinking of you, my friend, and wishing you all the very best on your recovery. Looking forward to seeing you back at your best very soon. Your pal, Tony."
Hetfield has battled addiction since Metallica earned a reputation in the '80s as being one of the best in the business when it came to alcohol abuse. The front man famously entered rehab in 2001 and considered leaving music altogether before reconvening with his band mates to complete the St. Anger album.
Iommi's own band famously battled addiction issues. The band fired Ozzy Osbourne in the late-'70s due to his drug abuse. Co-founding drummer Bill Ward left the band in 1980 due to his own alcoholism. Ward once said booze was the "most damaging" thing to Black Sabbath's legacy.
Lamb of God front man Randy Blythe recently credited Hetifeld and Metallica's road crew with helping him get help for his own alcoholism. Blythe revealed in a comment on Instagram that he was in a dark place personally when Hetfield offered to help him while the two bands were touring together in 2010.
He said Hetfield and Metallica "babied him" through his first month of sobriety and that he "couldn't have done it without them."
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