Photos: Nick Cannon spends 30 HOURS getting more ink added to his back.

He revealed he'd covered up his 'Mariah' tattoo with a sprawling Crucifix inking not long after calling it quits with the pop diva last year.

Now, Nick Cannon has gone back back under the needle to finish off his ever-expanding back tattoo. 

In a process that was captured for Urban Ink Magazine's March 24 issue, the 34-year-old sat for a staggering thirty hours at a Covina, California tattoo parlour to add a few final touches, according to TMZ