Jessica Biel will not climb Mount Kilimanjaro again.

The 'Valentine's Day' actress was glad she scaled Africa's highest peak, but the physical challenge left her "miserable".

She said: "I'm never going to that again. I just got back six days ago. 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."

She added to Access Hollywood: "Hiking for seven hours a day and sleeping in tents and being out in the wilderness was a real experience everyone should try."

Jessica undertook the trek up the mountain to raise global awareness of the world's water crisis alongside actor Emile Hirsch and other philanthropists including Kick Kennedy - granddaughter of Robert F. Kennedy and executive of the UN Foundation Elizabeth Gore.