Why would Justin Timberlake skip the January 24 afterparty for his new drama, Black Snake Moan, after it premiered at the Sundance Film Festival? You would too if you had Jessica Biel waiting at home for you.

Tinseltown’s sexiest bachelorette flew in that very night to stay with the boy-bander-turned-actor at his $1,950-a-night, four-bedroom condo at the Trail’s End Lodge in nearby Deer Valley.

“He called her and asked her to come,” says a source close to Biel, 24, who was spotted snowboarding with Timberlake, 26, the next day at the picturesque Park City Mountain Resort. “And she was like, ‘What the hell? I’ll go!’ She is really spontaneous and fun.”

Though the two rarely left their cozy digs, a mutual pal who spent time with the couple tells Us, “their relationship looked like it was definitely working for them.”

The pair stayed until January 26 and, says a source at the resort, “Justin and his group were fantastic guests.”

Biel’s rep, who won’t comment on Timberlake, tells Us, “Jessica was in Sundance for a couple of days to see some movies.”

Is the relationship serious? What makes Biel a better match for Timberlake than his ex Cameron Diaz? What controversy did the 7th Heaven star cause in 2000 that infuriated the show's creator, Aaron Spelling? For more details on Jessica and her romance with Justin, pick up the new issue of Us Weekly, on newsstands this week.

Talk to Us: Do you think Jessica should have agreed to join Justin on vacation or are they moving too fast?

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