The pair's relationship first came to light in 2007, when Timberlake, 30, and Biel, 29, were spotted together in Utah at the Sundance Film Festival. The pair remained one of the most visible couples in Hollywood until last March, when they decided to take a three-month break. But destiny is destiny, and by the fall they were together again, even double-dating with Biel's parents in October.
"When they reunited, they had a conversation about taking the next step," an insider told the magazine.
Just last month, the pair were more than cozy at a dinner for luxury leather brand Tod's at the Chateau Marmont. Meanwhile, rumors of an engagement first surfaced in mid-December, when it was reported that Timberlake had proposed to Biel while at the five-star Amangani Resort in Wyoming; those rumors may prove to have been well-founded.
In June, the typically private Timberlake made it clear to Vanity Fair that Biel still held a special place in his heart -- even though at the time the pair had called it quits.
"She is the single-handedly most significant person in my life ... In my 30 years, she is the most special person, ok? I just don't want to say much more, because I have to protect things that are dear to me - for instance, her," he said.