Russell Brand & Katy Perry -- Divorce Rumors have Ring of Truth

Rumors that Katy Perry and Russell Brand are calling off their marriage have just been fueled by explosive new photos ... of Russell in London ... NOT wearing his wedding ring.

The "Get Him to the Greek" star was in the West End earlier today, half a world away from his wife, who has been vacationing in Hawaii ... wearing nothing but bikinis.

The couple spent XMAS 7,000 AAdvantage miles apart. They tied the knot just over a year ago last October.