The pictures, posted to Twitter, show the legendary actor alongside McGregor after he broke his leg during UFC 264.
One shows McGregor wearing a cast, and sitting in an electric wheelchair as he waves Arnie off.
Another shows the pair chatting as McGregor sits on a hospital bed.
“I’ll be back! For the sake of humankind! I must return,” McGregor’s tweet reads.
“Happy birthday my man, @Schwarzenegger! Hope you and H are proud of my recovery/work and my latest move on the board.”
“Fun times ahead, bring it.”
In a subsequent tweet, featuring a picture of McGregor in combat with Gabriel Gonzaga, the 34-year-old said he cannot believe he’s about to “hit Hollywood.”
“Throwback to me vs Gabriel Gonzaga in Japan, I can’t believe I’m about to hit Hollywood. I will do you all proud.”
The tweet appears to be in reference to Conor’s debut appearance in a Hollywood production.
However, it appears the UFC fighter is insisting he won’t allow his acting career go to his head, as he promised never to forget about his first love, MMA.
“MMA, I’ll never forget you! Easy work.”
The UFC star is set to join Jake Gyllenhaal in a new remake of the classic 1989 action flick Road House, which is being made by Prime Video.
Road House will follow a former UFC fighter, played by Gyllenhaal, who takes a job as a bouncer at a rough-and-tumble roadhouse in the Florida Keys, but soon discovers that not everything is what it seems in the tropical paradise.
It remains unknown who McGregor will be playing in the project, but sources have made it clear that he would be playing an original character and not himself.
Insiders say when he heard there was interest for him to join the Road House cast, he watched the original film for the first time and enjoyed it so much he wanted to get in on the action.
Sources add that after a meeting with producer Joel Silver, McGregor was sold on the project and loved the idea of where the new story was headed compared to the original.
The Amazon Original Movie is set to go into production in the Dominican Republic this month and will stream on Prime Video in more than 240 countries and territories worldwide when it is released.