Morgan Brittany (born Suzanne Cupito) is an American actress born in Los Angeles. She is known for her role as Katherine Wentworth, the scheming younger half-sister of Pamela Ewing and Cliff Barnes, on the prime-time soap opera Dallas. Morgan Brittany (born Suzanne Cupito) is an American actress born in Los Angeles. She is known for her role as Katherine Wentworth, the scheming younger half-sister of Pamela Ewing and Cliff Barnes, on the prime-time soap opera Dallas.