Bell, 25, is the star of the current blockbuster "The Adventures of Tintin." He is best known for his work in the movie version of "Billy Elliott."
Wood, 24, is a member of the cast of TV's "True Blood."
UsMagazine.com published a photo taken Saturday of the couple with Wood wearing a dazzling new ring, but the celebrity news Web site said Wood's representative declined to comment on its report.
Bell and Wood met in 2005 and dated for a year starting in 2006, then broke up and reconciled last summer. Wood was previously engaged to shock rocker Marilyn Manson.
Attkisson leaves CBS News, reportedly over network's 'liberal bias'
Ohio bar shooting arrested, charged with murder