Dhoni stunned his team-mates and the cricket world when he announced his retirement from the five-day format after the Boxing Day Test against Australia at Melbourne Cricket Ground (MCG) on December 30, 2014.
Kohli, who was the vice-captain of the team and having already led the team in the opening match of that series was the automatic choice as full-time skipper.
On that day at MCG, Kohli, like others, was taken by surprise over Dhoni's decision. And few hours later when he knew he would be the captain in India whites, he cried.
"We were all taken by surprise (when Dhoni retired). My first feeling was: We played under him all this time. He has groomed all the young guys in the team. He has given them opportunities. And now he is not going to be the Test captain," Kohli told "Thecricketmonthly", the digital magazine of "ESPNcricinfo" in an interview.
"Honestly, I was not able to think that I am going to be the Test captain now, at that very moment. After things calmed down a bit, after about an hour and a half, I went to my room. Anushka (Sharma), who had come to watch that series, was there and I told her about the news.
"Her feelings were also mixed as to how did this happen so suddenly. Why did he do this? After a while for both of us it sunk in that I am going to be Test captain of India, not just for one or two games but permanently. And that is when I broke down, because I never expected this to happen," the right-hander added.
Kohli, who is gearing up for the tour of Bangladesh, said it was surreal to become Test captain at a young age of 26.
"Honestly, if you told me when I started playing cricket that at 26 I will be Test captain of India... no chance. My only dream was to play Test cricket for India. It is amazing how all those feelings as a young kid, playing club cricket, playing school cricket, playing state cricket, all those memories start flashing in your head.
"How many games you played. How you came up through the ranks. How you came up at different levels in cricket in India. And this day and this moment is in front of you. It was surreal. It was a special sort of emotional feeling that I experienced," Kohli said.