Stephen Moyer, Anna Paquin and Alan Ball
Sara De Boer/Retna
10/11/2009 AT 11:15 AM EDT
They purposely played down their romance on set – even fooling their costars
– but True Blood
creator Alan Ball says he was on to Anna Paquin and Stephen Moyer from the start.
"I know that they think that
nobody knew about it until the end of the season," Ball tells PEOPLE at the 5th annual GLSEN Respect Awards in Los Angeles, "but I knew about it by episode two."
Ball, 52, sensed a connection between the stars after filming the scene where their characters first meet. "Stephen comes into the bar, and takes [Anna's] hand, [and] I
thought, "Wow, they have chemistry!" But sometimes actors have
chemistry when they're acting together, but they cannot stand each
other while off set."
Not the case here, it turns out, of course.
"When I found out that they were dating," Ball says, "my reaction was, 'Uh-oh! I hope that this doesn't blow up in our face.' "
"But this has been happening long enough that it's very clear that it
is the real thing," he says of the engaged duo.
"They're very, very happy, and I'm just
thrilled for them."