Credit: Kevin Mazur/

Er, sounds romantic!

What are sweethearts Jessica Biel and Justin Timberlake doing for Valentine's Day? "No plans!" Biel told at Monday's Hollywood premiere of ahem, Valentine's Day, in which she costars.

"I'll actually be working," the actress explained.

Not that Timberlake's love of three years isn't a fan of the February 14 holiday that inspired her new, all-star romantic comedy.  "I love it!" she gushed. "It's great to take a day out and celebrate loving and caring for people...It's great!"

In the January issue of Vogue, Biel, 27, cooed that Timberlake was "the most precious thing in my life." Although Timberlake, 29, wasn't by her side when she climbed Mt. Kiliminjaro Jan. 11, the couple was spotted "sitting close, holding hands and whispering" at a Radiohead benefit concert for Haiti in late January, according to eyewitnesses.

"Jessica was laughing at everything he said," says an observer. "She was always gazing at him."

The couple was first linked romantically in January 2007, following the end of Timberlake's nearly four-year relationship with Cameron Diaz.

Valentine's Day, which also stars Julia Roberts, Bradley Cooper, Jennifer Garner, Jessica Alba, Taylor Swift, Ashton Kutcher, Jamie Foxx and others, hits theaters this Friday.