The rocker kept quiet about the medical procedure so as not to jeopardise tour dates or worry fans, but now he's confessing the Final Tour dates so far have been tough for him.
In a post on Facebook.com, Sixx reveals he has undergone surgery while the band is on a short break, and he's hoping his pain issues will soon be a thing of the past.
He writes, "I have been performing during the last few months with a pretty intense double hernia, but you gotta give 100% even through the pain onstage. The good news is yesterday I got surgery on both sides and it went really really well."
But Sixx admits he's still in agony 24 hours after the operation: "Holy Jesus, it feels like I got kicked in the stomach by a horse."
Motley Crue's dates will resume on 10 October (14), and the bassist hopes to be fully recovered by then, adding, "I should be up and kicking a** in a few weeks and back in the gym/tour in six weeks. Looking forward to seeing you all back out on the road."
It has been a crazy few weeks for the rocker - his new wife Courtney Bingham recently announced she's pregnant, while his ex, Brandi Brandt, has been sentenced to six years behind bars in Australia for her role in an international drug trafficking ring.