Drew Barrymore Engaged to Will Kopelman
01/05/2012 AT 01:30 PM EST
The couple got engaged in Sun Valley, Idaho, a source tells PEOPLE.
Kopelman proposed with a colorless radiant-cut diamond ring by Graff.
"They are very happy together," adds the source.
Barrymore spent about 10 days over the Christmas holiday in Sun Valley with Kopelman, where they were spotted at the romantic Vintage restaurant and picking up organic salads at Kiki's Café. Onlookers tell PEOPLE when spotted out and about, the couple graciously posed for pictures.
Though the two never officially confirmed their relationship, they have been linked romantically since February of last year.
For most of 2011, they were nearly inseparable, spotted everywhere from Broadway shows to sporting events together.
It will be the third time down the aisle for Barrymore, 36, who was married to Tom Green from 1999 to 2001 and to Jeremy Thomas briefly in 1994.
Barrymore's rep didn't immediately respond to request for comment.
With Reporting by JEN LIEBRUM