Credit: Dan MacMedan/

Justin Timberlake wasn't by Jessica Biel's side when she reached the tippity-top of Mt Kiliminjaro Jan. 11 -- but now that she's back from Africa and closer to sea level, the couple are enjoying one another's company again.

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On Sunday, the pair co-attended Radiohead's Haiti benefit concert at the Box at the Henry Fonda Theater in Los Angeles. "They were definitely couple-y," an observer at the Box tells "They were sitting close, holding hands, and whispering." They weren't the only A-listers enjoying the band: Maggie Gyllenhaal and Peter Sarsgaard, Kate Hudson, Charlize Theron, Anna Paquin and Stephen Moyer, Daniel Craig, Patricia and Rosanna Arquette, Famke Jansen, Busy Philipps, Flea and No Doubt's Tony Kanal all attended as well.

Timberlake flew solo the night before at the all-star Hope for Haiti Now telethon, where he had a friendly, no-drama reunion with Cameron Diaz, his girlfriend before Biel.

But at the Radiohead show, he and Biel "were walking around taking pictures together and never really left each other's sides the whole night."

The sometimes reclusive pair "were low key but very cordial," a concertgoer says. "[They] didn't mind talking to people that came up to them."

Biel, who has said Timberlake is "the most precious thing in my life" appeared transfixed by her man. "Justin was holding court and Jessica was laughing at everything he said," says the eyewitness. "She was always gazing at him."

Radiohead's concert reportedly raised over $500,000 for Haiti relief through Oxfam America. To help earthquake victims now, consider visiting Oxfam's website and donating today.