'Celebrity Rehab' Star Shifty Shellshock -- Out of Coma

Former Crazy Town singer and "Celebrity Rehab" star Shifty Shellshock is now conscious again -- after falling into a coma last week, TMZ has learned.

Sources tell TMZ, Shifty had been on breathing tubes since Thursday -- when he originally fell into a coma -- but was successfully taken off them last night.

We're told Shifty is now responsive -- even speaking sporadically -- but he's still not fully aware of his surroundings. He is still in the ICU.

As we previously reported, it's unclear what put the singer into a coma -- but several people close to him are convinced drugs were to blame.