The break was mutual, the site reports, and they remain on good terms.
Biel and Timberlake have dated since 2007, though it's been a rocky relationship at times. In late 2010, it was rumored that Timberlake had cheated with Olivia Munn; his rep soon denied it, but in January Life & Style reported that Timberlake told Munn, via text message, that his relationship "was over."
There were rumors that the pair had split in 2009, too; Us Weekly reported that Biel was in denial, though again, they were soon spotted vacationing together in Napa and enjoying romantic meals.
In 2010, Biel spoke with Vogue, gushing about her private relationship with Timberlake.
I don't want to talk about it," she said. "I don't feel the need to clear anything up. It's the most precious thing that I have in my life, and I care about it so much that I don't care about what anyone says or thinks. I have just not addressed it in any real way, and I'm not going to. It's mine. And I really like that about it."
In addition to TMZ, Us Weekly now reports that this time, the split is for real.