McGregor shared several intimate family snaps from the hospitalCredit: Instagram @thenorotiousmma

McGregor tweeted: “My baby boy is born! Mammy and baby doing amazing, 8.1lbs of prime Irish double champion beef!”

A couple of hours later, ‘Notorious’ made a separate post on Instagram where he shared pictures of his newborn and praised his fiancée.

“Another chunky healthy boy into the world. Dee you are my hero [heart and praying emojis],” McGregor captioned the post he shared with his 47million followers.

UFC fighters, past and present, flooded McGregor’s comment section with kind messages, but it was Jose Aldo’s one-word reaction that caught the attention of MMA fans.

“Congrats,” the former featherweight champion simply commented on the birth announcement post alongside waving and heart emojis.

One fan replied: “LOVE THIS.”

Another said: “Respect.”

A third person commented: “Wow. You’re a beast for this.”

‘Notorious’ verablly tortured Aldo during their world tourCredit: getty

One shot was all McGregor needed to end Aldo’s decade-long winning streakCredit: getty images

McGregor and Aldo have become unlikely friends in recent years.

In 2015, they were mortal enemies forced together for a press tour that almost got out of hand when the Irishman stole his rival’s UFC belt during a press conference.

After months of mental warfare, they finally settled their differences at UFC 194, but the eagerly anticipated fight was over after just 13 seconds.

McGregor brutally knocked out Aldo, who hadn’t lost a fight in 10 years, with one punch to become the UFC’s 145lb king and continue his journey to superstardom.

Since then, McGregor has won UFC gold at lightweight, made $100 million boxing Floyd Mayweather, and become one of the richest sportspeople on the planet.

During that time, the 35-year-old squashed his beef with Aldo by sending him a gift following his interim featherweight title win over Frankie Edgar in July 2016.

McGregor has publicly backed the Brazilian before and after many of his big fights since then, and he was one of the first people to congratulate Aldo when he was inducted into the UFC Hall of Fame.

The former rivals have become each other’s loudest cheerleaders as they set about achieving new goals in sport and life.