A former alley cat taken in by a wealthy woman has become the world's richest cat because it has inherited a $13-million fortune following the woman's death.

Tommaso, a 4-year-old black cat, is also the world's third richest animal.

Its owner 94-year-old owner, Maria Assunta, died last month and left her fortune the beloved kitty.

Two years ago when Assunta's health started to deteriorate she wanted to make sure that Tommaso was fully taken care of. She wrote a will in November 2009, leaving all to Tommaso.

Prior to that Assunta had instructed her lawyers to identify an animal welfare association or group where she could leave her estate with the commitment that they will take care of Tommaso. She couldn't find one and so the money went to the cat and a woman called Stefania was entrusted to take care of Tommaso.

Stefania, a nurse, also took care of Assunta until her last days. But the nurse said she had no idea Assunta was that rich.

She had become very fond towards the nurse who assisted her, Anna Orecchioni, one of the lawyers, told Il Messaggero newspaper, as reported by 39Online.com. We're convinced that Stefania is the right person to carry out the old lady's wishes. She loves animals just like the woman she devoted herself to right up until the end.

Stefania said Assunta suffered from loneliness and that she looked after that cat more than you'd look after a son.

The Guardian reported that Assunta was a childless widow of a successful builder.

The money she left Tommaso places him behind Kalu the chimp, whose owner left him $80 million dollars, and Gunther IV, a German shepherd who inherited $372 million dollars from his father, Gunther III, who got a windfall from a German countess, according to reports.