The Illusionist actress hiked to the top of the 19,340-foot-high (5,895-metre) Tanzanian peak with a team of celebrities, including actor Emile Hirsch and rapper Lupe Fiasco, for a charity campaign last month (Jan10).
But she won't be revisiting Kilimanjaro in the future - because finishing the mission was too physically demanding.
She says, "I'm never going to do that again... It was incredible. It was such a challenge for me. It was probably one of the hardest things I've ever done... sometimes it was kind of miserable.
"Altitude sickness is like a general uncomfortable, uneasy feeling. You just can't think straight. (But) hiking for seven hours a day and sleeping in tents and being out in the wilderness was a real experience everyone should try."