The Armenian international, who previously played with Ozil while the pair were at Borussia Dortmund, has said that it was a "dream" to be reunited with the German.
"Everyone knows that Mesut is one of the best players in the world," Mkhitaryan told Arsenal Player. "It's only happiness and joy to play next to him because he understands very well the football game, he has great vision, he has amazing technique and he's the best in his position.
"I thought it could only be in a dream that we could join another club other than Dortmund but I am very happy for that. I know him very well, he is one of my best friends and one of the best team-mates I have ever had.
"I am very happy to have him here and I think all the fans are happy to see him in an Arsenal shirt. What can I say? I love playing with him."