The 34-year-old British actors used to share a flat in London's exclusive Primrose Hill area.
Although the pair moved out because their lives went in different directions, Cooper still misses his friend's unique daily wake-up call, reported Contactmusic.
"He would do a full dive on the bed. We lived together for ages, but were both extraordinarily busy, so kept missing each other. I started to think I should move when there was a cot at the end of the bed," Cooper said.
The actors became close while starring in Alan Bennett's play 'The History Boys' in 2004 - which was turned into a popular film in 2006.
Their profiles have been on the rise ever since, yet Cooper still has fond memories of their poverty-stricken days as struggling actors.
"It was lovely, but it had no furniture, so we'd sit on the floor eating baked beans. They were a mixture of very happy and very lost times," Cooper said.
