Conor McGregor Mourns the Loss of Dog Hugo: 'My Closest Companion'

Conor McGregor's dog Hugo has died.

The 33-year-old MMA pro announced the sad news on Instagram Wednesday, alongside a series of pictures on both his grid and Instagram Story.

"So heart broken to say my dog Hugo has passed away. He was with me all the way, my closest companion," McGregor wrote in the caption of his post, which began with a photo of him and Hugo laying in bed together.

"From sleeping on a bed frame without a mattress to everything else that came after. Thank you for all the work put in alongside me to get this life correct for our family. All the love and cuddles we will miss forever and ever our Hugo! Gutted 💔."

The former UFC champion concluded, "RIP the best boy Hugo McGregor 🙏."

The series of snapshots throughout the years featured one of McGregor and his four-legged friend running alongside each other as well as another of the pair at the gym.

RELATED VIDEO: Conor McGregor and Fiancée Dee Devlin Welcome Third Baby, Son Rían: 'Family of 5'

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Friends and fans sent their condolences to McGregor in the comments section of his post. Fellow fighter and longtime pal Dillon Danis wrote, "Sorry brother he will be missed ❤️," while Irish professional football coach Robbie Keane said, "I know how you feel pal 💔🙏."

The mixed martial artist also shared a sweet video of Hugo lounging outdoors on a couch, which was set to the Ed Sheeran song "Runaway."

McGregor captioned the clip, "We got there in the end my boy 😍."

In May, the fighter and his fiancée Dee Devlin announced the birth of their third child, baby boy Rían, who joined brother Conor Jack Jr., 4, and sister Croia, 2.

The dad of three shared the news with a sweet photo on Instagram of him cradling his son.

"The McGregor Clan is now a family of 5 ❤️ Healthy baby boy delivered! Baby and Mammy Wonder Woman are doing great!" McGregor wrote alongside the photo. "God I thank you for everything you give to me and my family in this world 🙏 My new born son, Rían McGregor ❤️."

On Christmas Day 2020, McGregor announced on Instagram that he and Devlin were expecting their third child. The star shared a photo of his family dressed in matching Christmas pajamas with their son holding up an ultrasound image.

"Happy Christmas everyone, from my family to yours ❤️. So much to look forward to in 2021 👶," McGregor captioned the photo. Devlin reposted the photo to her Instagram page, writing "Merry Christmas! ❤️."