"Just when we thought she was getting better, things took a turn for the worst, and she passed peacefully, surrounded by those who love her," she wrote. "If you ever met Peps, you'd know she was such a special girl. She was smart, sassy, and loved cuddling. She enjoyed playing in the yard with our Labrador, Hank, and would make everyone laugh with her surprisingly speedy 'zoomies' around the house."
She continued, "She also had a unique way of expressing herself with funny little noises that sounded like they were from some sort of pigeon. Pepper was simply the best, and I repeatedly told her how perfect I thought she was."
Ava also noted Pepper got her through several "tough times" including her formative teen years.
"I am forever grateful for our bond," the University of California, Berkeley student wrote. "I'll always treasure the times when I'd come home from college and she would meet me at the door, jumping for joy, and I'd pick her up so she could lick my face. She really knew how to make me feel special!"
She ended the post on a positive note, however, by acknowledging, "As sad as I am and as much as I've cried over losing her, I am happy she had such a great life and is no longer in pain. [red heart emoji] Love you forever, miss Peps."
A tried and true animal lover, Reese's Instagram feed is filled with photos of their family's beloved pups, including Pepper.
Just last week, she and the pooch posed for a sweet selfie, which the actress captioned, "Pepper wanted to check in with y'all and see how everyone's doing."
In her own tribute to Pepper, Reese wrote, "Our sweet Pepper passed away yesterday. My goodness, she was such a loyal and devoted family member. I am so heart broken, but I am also deeply grateful for all the love and comfort she brought our family. Now she's in dog heaven where all great pets go. Chasing tennis balls, running through open fields of wild flowers and being the Queen that she is. That's what I believe. We will always love you, Pepper."