They may be having marital problems on the set, but... at least they're good friends off it! T.R. Knight (George) and Sara Ramirez (Callie) are seen in the photo below at the 23rd annual AIDS Walk Los Angeles, which took place October 21.

The event, attended by this pair of Grey's Anatomy cast members as well as other celebrities, set fundraising and attendance records, raising more than $3.9 million for AIDS Project Los Angeles and other AIDS service organizations.

Steve Marsi is the Managing Editor of TV Fanatic. Follow him on Google+ or email him here.