After guest starring in a handful of episodes, ABC has brought Rob Lowe on as a regular on the ABC hit drama, Brothers & Sisters.

He plays conservative Senator Robert McCallister, a John McCain-style Republican, who has forged a professional, and possibly romantic relationship with Calista Flockhart's character, talkshow host Kitty Walker. Lowe's presence has helped the show in the Nielsen voting booth, adds Variety, matching its series highs among adults 18-49 on November 19th, when he first appeared.

Lowe will continue to be labeled a 'special guest star' and remain on Brothers & Sisters through the end of this season; it airs Sunday nights on ABC.