One source told Us,
This is something they both wanted. They are both so happy.
Another told People
They are both very, very happy. It’s still early.
When asked about last week's rumors that the couple was expecting twins, the second source replied,
No, not twins.
Another friend told People,
It won’t necessarily be a short engagement. They haven’t begun planning the wedding yet.
Kutcher and Kunis first met on the set of "That ‘70s Show" in 1998. They remained friends after the show's end, and began dating after the highly publicized divorce between Kutcher and Demi Moore.
Kutcher currently stars in the series "Two and a Half Men," and also starred in the title role of "Jobs," a Steve Jobs biopic. Kunis, of course, continues to star as Meg Griffin in the series "Family Guy," and was critically acclaimed for her role in "Black Swan." She was Esquire's "Sexiest Woman Alive" in 2012.