Zachary Quinto is mourning the loss of his "true prince," his beloved dog, Noah.

The "Star Trek" star took to Instagram to share a selfie with Noah. In doing so, he revealed that his bark-ner in crime had been put down.

"Anyone who has ever truly known me in the last 14 years has known this true prince. noah has been by my side through up and down. thick and thin. feast and famine," the heartbroken actor wrote. "In loving him i learned to love myself more fully. he taught me compassion and patience and generosity..."

He continued of Noah, "And oh how he made me laugh. he made friends wherever he went. his spirit was pure. his love was legend. i am a better person for having had him in my life. but tonight we had to let him go. surrounded by love he went to sleep. and may he forever rest in peace."

Zachary's boyfriend, Miles McMillan, also shared an online tribute to the Irish Wolfhound-terrier mix on April 20.

"We had to say good bye to our dear sweet Noah last night," Miles wrote. "He was surrounded by love flowers and music. I'll always remember his big grin and how happy he always was to get a little lovin'."

Joseph Marzullo/WENN.com

In 2009, the actor gushed about his dog to People magazine.

"I love to run with my dog," he said. "And sometimes, I just hang out. When I'm working, it's whatever I have time for."

His dog, he said, is always by his side, even when paparazzi surrounded him.

"I think everybody has seen pictures of themselves and goes, 'What was I thinking?'" he told the mag. "But honestly, most of the candid pictures I've seen of myself have just been me walking my dog. That's basically how I spend a lot of my time."