Jessica Biel and Justin Timberlake
may have said
only last year, "I was never one of those girls who dreamt of my wedding and my Prince Charming," but it looks like she's about to have both.
Biel and Justin Timberlake
are engaged to be married, a source tells PEOPLE.
The big moment happened while the on-again couple were in Big Sky Country, on their annual vacation to Montana, according to the source, who reveals Justin proposed with a "custom-designed" ring.
Timberlake, who turns 31 later this month, and Biel, 29, celebrated the happy news with friends.
Only a few weeks ago, unconfirmed reports said the longtime romantic couple
were altar-bound, but the rumors proved premature.
Last year, the couple spent time apart for several months
after being together for four years, since May
. They made their split official
in March 2011.
Still, over that summer, Timberlake told Vanity Fair
about Biel, saying, "She is the single-handedly most significant person in my life. In my 30 years, she is the most special person, okay? ... I don't want to say much more, because I have to protect things that are dear to me – for instance, her."
By the following September, the two were back on and publicly affectionate
When they were spotted having brunch last fall in a Colorado mountaintop bar, an onlooker told PEOPLE, "There was plenty of P.D.A., and they seemed happy." Other sightings soon followed in Las Vegas
, in New York
and in Hollywood