Uggie the Dog Dies -- 'The Artist' Star Put to Sleep After Prostate Illness

Uggie, the famous Jack Russell Terrier from "The Artist" ... has gone to the big doghouse in the sky -- after bravely battling a prostate tumor.

TMZ has learned the 13-year-old star who played "The Dog" in the 2012 Oscar winning film was put down Friday in Los Angeles. His owner, Omar Von Mueller, tells us it was a difficult decision, but Uggie had been suffering with the tumor, and the last few weeks were especially difficult.

Sarah Clifford worked with Uggie on his big star turn, and tells us he was "a perfect little terrier" with boundless energy.

His "Artist" work earned him several accolades, including a Golden Collar Award ... and the Palm Dog Award at Cannes. He also famously nipped at Harvey Levin during a visit to TMZ Live.

Uggie was able to cash in on all that success too -- becoming Nintendo's first ever spokesdog.

Clifford added ... "I will forever hold him dearly in my heart and never forget his infinite love for chicken and hotdogs."

R.I.P. little guy.