But the Irish fighter's post was met with outrage by many of his fans on Twitter.
McGregor's followers did not hold back in their criticism of his gushing tribute to Putin, a leader who has been criticised for his reported anti-LGBT stances, his alleged human rights violations, and claims of clamping down on free speech, especially in the media and on social media.
Fans' comments ranged from the cautious 'Yikes man, Yikes' to the outraged 'What the f*** Conor?'
One fan told Conor he should be ashamed of himself, while another simply said: 'Shame on you champ!'
Another said: 'What a twat! Unfollowed' while another was vitriolic in his criticism, declaring: 'F*** YOU !!!' in all caps.
Another commenter weighed in with: 'Totally uneducated, and to stuck in his own bubble to know what's going on in the world. Unfollow.'
McGregor's week got off to a fairly good start. He was fresh off his trip to Vegas where he celebrated his friend's 30th birthday.
On Saturday, the so-called champ champ himself turned 30, and on the same day his girlfriend Dee Devlin announced that she was carrying his second child.
In a birthday tribute on Instagram, Dee, who has been with Conor for almost 10 years and is mother to his son Conor Jr, wrote: 'Happy 30th birthday babe! Thank you for being you! Love you to bits from me, Conor jr and the bump' alongside a photo of McGregor on a luxury yacht.
