Carrie Underwood Mourns the Death of Her Dog Ace: 'He Will Forever Live on in Our Hearts'

Carrie Underwood is paying tribute to her dog Ace following his death on Sunday.

The singer, 39, shared a series of photos of her beloved pet, including a shot of her kissing his head, on Instagram Monday.

"Last night my sweet Ace left this world…he will forever live on in our hearts and be forever missed," the Grammy winner captioned the images. "He was there for me when I was on my own trying to figure out life when it was at its craziest! He was with me through 3 houses, 6 tours and 2 kids…always ready to snuggle and play…through all the highs and lows."

She added, "He was a true friend and a good boy till the very end. I love you, sweet Ace…see you on the other side…💔"

Fellow country singer Miranda Lambert shared her condolences in the post's comments section.

"🙌😢so sorry. I know how bad that hurts. Sendin love your way," she wrote.

Underwood and her husband Mike Fisher — who share sons Isaiah, 7, and Jacob, 3 — attended the Grammys on Sunday night, where the singer performed her song "Ghost Story."

Ace played an important role in Underwood's wedding to Fisher in July 2010, serving as a ring bearer alongside Underwood's nephew. The flower girl was responsible for holding Ace's leash.

"He'll be one of the ring bearers — he's like my kid," Underwood said before the wedding. "Ace is such a big part of my life."

Ace dressed up in a custom powder pink tuxedo for the big day and wore a white gold and diamond "A" designed by jeweler Johnathon Arndt.

"Mike was like, 'He's in pink! What are you doing?' " Underwood told PEOPLE at the time. "But he looked so handsome."

"He needed a little bit of coaxing along the way, but he did great," Fisher added. "It was cute — it was a cool moment. Everybody really loved it."