I'm trying to remember a 70's sci fi TV feature. The premise of the show had two warring planets settling their differences on Earth secretly. They were to each send 4 or 5 agents who would battle to the last man and the winner would either win their war, or get Earth. The last guy had fallen for an earth woman who (surprise)...

>!...is an enemy alien in disguise, and kills him at the end. 

Any idea what it might have been called?