02/03/2012 at 02:00 PM EST
has some new bling, but don't get too excited: It's not from Justin
The actress, who has yet to be spotted wearing an engagement sparkler
, was sporting a ring on the set of her new movie Emmanuel and the Truth About Fishes
, filming in L.A. Friday, but it's just for the role.
The thriller, which also stars Alfred Molina, is reportedly about a woman who develops an obsession with her new neighbor who resembles the woman's dead mother.
Off-camera, Biel has been noticeably spotted without any engagement ring. At the Golden Globes
, she wore a ton of Tiffany & Co. jewelry – including a diamond ring in platinum – but her left ring finger was bare. The actress made other public appearances, including a party at the Chateau Marmont, sans ring that weekend as well.
Timberlake, 31, proposed to Biel, 29, during the couple
's annual vacation in Montana with a custom-designed ring, a source confirmed to PEOPLE in January.