Katy Perry, Russell Brand -- Officially Divorced

Katy Perry and Russell Brand have officially severed ties -- their divorce became final today.

Russell filed for divorce at the very end of 2011, and the settlement was hashed out quickly, but it takes a full 6 months before a divorce in California can become final.

We broke the story ... even though there wasn't a prenup, Russell walked away from half of the $44 million fortune that Katy racked up during their 14-month marriage.

Even though they had to wait for a legal divorce, they didn't wait to move on. Both have been seeing other people for months.