Danny Masterson and his girlfriend of eight years, Bijou Phillips, tied the knot Tuesday before an intimate group of family and friends in the Irish countryside, their rep confirms exclusively to PEOPLE.

In a nod to Masterson's Irish heritage, the couple had a formal wedding at a private castle, the picturesque setting of Tipperary serving as their backdrop, during a weeklong celebration.

Phillips, 31, wore a custom Zac Posen gown and Masterson, 35, donned Albert Hammond Jr. for Confederacy.
The groom’s brother Chris Masterson served as best man and guests included actors Ben Foster, Mike Pena and Ethan Suplee and acclaimed artist Gottfried Helnwein.

Masterson “proposed” to Phillips, his costar in several films, in March 2009.