After reaching the peak of Mount Kilimanjaro, Jessica Biel has set her sights on a new challenge — a little mountain called Everest.

“I would love to trek to an Everest base camp,” the actress, 28, told UsMagazine.com at the premiere of Summit on the Summit, a 90-minute documentary about a crew who climbed 19,340 feet to raise awareness about the global clean water crisis, in New York City Wednesday.

Although she says the Everest trek is her “next goal,” it’s actually less intense than her six-day trek with fellow actors and musicians in January because the point she hopes to reach stands at 17,000 feet — 2,000 less than the summit of Kilimanjaro.

“I feel like I could handle that a lot better for a longer period of time, so that’s my next expedition,” she tells Us.

The hardest part about these climbs, she says, wasn’t the physical challenges.

“It was really mental,” she says of her Kilimanjaro climb. The key, she adds, is “to not let your brain play a trick on you — to keep motivated — to keep inspired even when you’re feeling nauseous and your head hurts and you’re uncomfortable thinking, ‘What am I doing here? This is crazy? This is really, really hard!’”

So, has she been able to show off her physical fitness gains during joint training sessions with beau Justin Timberlake?

“No,” she tells Us, laughing. “We really enjoy our workouts… It’s not a competition.”

She says their personal trainer, Jason Walsh, “is amazing” and “does such a good job keeping us motivated.”

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A premiere party for Summit on the Summit: Kilimanjaro was held tonight in New York City, and Jessica and CO. went to the party! Jessica looks gorgeous in a flower printed dress and blazer.  She was also quoted by MTV saying:

“She was like this mysterious, foreboding, ominous woman. And she was hidden almost all day long, and just when you were unmotivated, and feeling like crap and uninspired and thinking, ‘What am I doing here?’ the clouds would part and she would peek out, and the beauty would strike you, and then you’d be inspired again,” Biel told MTV News on the red carpet for the premiere of “Summit.” “And she was literally, like, this woman who would pull this veil over her face and disappear, and then she’d show a little bit of herself, and then she’d disappear again. It was kind of this running joke, but I really felt that way. I felt like, ‘I respect you. Please let me get up, please.‘ “

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Yesterday, Jessica and Co were on CNN’s “Larry King Live” to promote the upcoming MTV documentary, Summit on the Summit! Jessica looked beautiful as she discussed how and why she did the climb – I’ve embedded a video and have also added screen caps!

Enjoy!

• Jessica Biel’s Personal Birthday Request!
• Watch Summit on the Summit online!
• Summit on the Summit – MTV Premiere Tonight
• Summit on the Summit: Kilimanjaro – MTV Trailer
• Premiere Of “Summit On The Summit: Kilimanjaro”