Alex O'Loughlin, who plays a vampire/private investigator, and Shannyn Sossamon star in the CBS drama that has lots of bite -- Moonlight.

Alex O'Loughlin plays a vampire in Moonlight, so it wasn't a stretch to assume he also had been on the Highway to Hell.

But contrary to persistent rumours, O'Loughlin -- whose show returns with a new episode tonight on CTV and CBS -- has insisted he is not really the son of deceased

AC/DC lead singer Bon Scott.

"It started with a friend of mine calling me, my best buddy (in North America) actually, and he was very upset," said O'Loughlin, was born in Australia, when asked last year about the rumour that -- much like a vampire -- refuses to die.

"He said, 'Do you have something you need to tell me?'

"He told me to go and Google-search my name, and the rock band AC/DC, of which he's a giant fan, and apparently according to the rest of the world and several big newspapers back where I'm from, I'm the son of the late Bon Scott.

"I was shocked, and then I was thrilled. I rock. Secretly I rock all the time."

Bon Scott died in 1980 at age 33. O'Loughlin was born in the mid-1970s, so the biological math could add up.

O'Loughlin actually was enjoying the notoriety, until his mom called.

"She was very upset at having been labeled a groupie, and therefore a hussy and a harlot, which isn't true at all," O'Loughlin said. "My mom is a very wonderful woman and very respectable.

"So I suppose it's probably a good time to say, since (Scott) has passed on and he can't speak the truth, that I should speak for Bon and say that I'm pretty sure he's not my dad."

Pretty sure? Well, that's just vague enough to fuel imaginations.

Certainly Moonlight has fueled some imaginations since hitting the airwaves last fall. While the ratings have been mediocre -- Friday is a lousy night for TV, after all -- the show has acquired a staunchly loyal cult following, and the creators hope to expand that fan base with four new post-strike episodes to complete the first season.

Moonlight follows Mick St. John (O'Loughlin), a charming and immortal private investigator from Los Angeles who defies his blood-sucking tendencies by using his wit and supernatural abilities to help the living. Moonlight also stars Sophia Myles as Beth, Jason Dohring as Josef and Shannyn Sossamon as Coraline.

The previous episode of Moonlight left off as Mick discovered Coraline's secret to being human, which left him to decide whether a chance at mortality was worth the steep price he would have to pay.

In the episode tonight, which is titled Fated to Pretend, Beth is kidnapped by a suspect in her boss' murder case and Mick is forced to decide whether saving her is worth sacrificing being human again.

O'Loughlin isn't surprised there are so many vampire tales still on TV and in theatres these days, since the dream of immortality lends itself to 21st-century plastic-surgery culture.

"It's certainly pertinent to what's going on in today's society with vanity," O'Loughlin said. "A lot of it is sort of drummed up and kept alive by the media and by us, by our demand for magazines. But also, a lot of it was born from the industry we're working in.

"(Mick) is 90 years old and he's still sort of ruggedly handsome, he's still youthful and his skin is still youthful and his eyes are still bright. But it's something that he struggles with. It's not actually something he ever really gets to enjoy."

In other words, it isn't as much fun as being the son of the late Bon Scott.

O'Loughlin's real father is a teacher at a private school in Sydney. But hey, there's no sense in letting the truth get in the way of a good pop-culture legend.