There's something about starring in a vampire-related film or television show that makes co-stars want to date each other. What's up with that? Maybe it's the allure of the vampires that somehow translates to real-life. Or it's all that bloodsucking.

Kristen Stewart dated Robert Pattinson when they were in Twilight, Nina Dobrev dated Ian Somerhalder during their days on The Vampire Diaries, Sarah Michelle Gellar was rumored to have dated her Buffy co-star, David Boreanaz. The most successful relationship out of them all came when Anna Paquin married her True Blood co-star and on-screen/off-screen love, Stephen Moyer.

Even though we haven't really heard from Paquin and Moyer recently, they're still in a successful marriage, raising their twins, and are co-producing a new Amazon Prime series, Flack. They might not be so thrilled about the supposed True Blood reboot, but other than that, everything seems to be hunky-dory for the couple.

Unlike their True Blood counterparts, though, it wasn't exactly love at first sight.

Was It The Rated R Nature Of The Show That Turned Them On To Each Other? No, It Wasn't

Paquin had similar thoughts to Nina Dobrev's when she first appeared on True Blood in 2008. She wasn't looking to date any of her co-stars, yet, it still happened somehow.

Unlike their characters, it wasn't exactly love at first sight (for Paquin at least) when they met on set. Paquin told Live with Kelly and Ryan that they first met during a screen test together (she'd already gotten the job but Moyer hadn't yet).

Paquin confessed that they got along really well, but when you sign a seven-year contract you kinda have to. You also probably shouldn't look to date them either. "It's not really a great policy. We're actually quite stupid for having done that," she said.

For Moyer, however, it was love at first bite. He describes that first screen test as having that special "spark."

Related: Anna Paquin Used To Be Everyone's Favorite Vamp Girl, Now She's A Ruthless Publicist

"By day three or four-oh, this is going to sound so syrupy – but I knew I wanted to spend the rest of my life with her. It was within seconds, really, and it just became a thing," Moyer explained on Watch What Happens Live. Soon Paquin couldn't deny it anymore and returned his feelings.

Many people probably think that they fell in love because they had to get to know each other really well in all those sex scenes in True Blood, but that's just not how it happened.

Even though Paquin and Moyer knew it wasn't smart to date each other, especially at the beginning of their contracts, they did it anyway. They clearly couldn't resist their attractions to one another, just like Dobrev and Somerhalder.

Also like Dobrev's relationship with Somerhalder, Paquin and Moyer tried to keep their relationship on the down-low for as long as they could.

Related: 20 Surprising Facts About Anna Paquin's Career

"It was very intentional on both our parts," Paquin said at the time. "It was very important to me that the cast and crew we were working with didn’t feel it was fickle. … We didn’t want to take anything away from the show."

But, unfortunately, the news got out quickly, after a year of keeping it quiet. Shortly after, they got engaged while on vacation in Hawaii and later tied the knot in 2010 with a private Malibu ceremony.

They Are Each Other's Best Friends

Since their marriage began almost 11 years ago now, the couple has accomplished a lot. They juggled the birth of their twins, Charlie and Poppy, who were born in 2012, while they finished True Blood in 2014, and are now co-producing Flack (in which Paquin also stars). But the most important thing is maintaining their marriage and staying best friends.

Speaking about the couple's secret to a successful marriage, Paquin told Us Weekly, "We’re each other's best friends. We’re incredibly lucky that we found each other. We want nothing but good things for each other. His successes are my successes and vice versa, and we’re just really lucky."

Besides this, Paquin and Moyer have agreed to keep their private lives, especially the lives of their children, a secret.

"Everyone chooses what works for their family. There are aspects of one’s private life that are fun and cute and not too revealing. And then there’s stuff where you’re making decisions for people who don’t have a say yet about whether they want to be in the public eye," Paquin told TODAY Parents in 2018.

"I’ve always been very private. I’m not as neurotic about it as I was when I was younger. I don’t want people to know too much about my real, inner private life. That’s part of having been a teenager and feeling constantly, brutally self-conscious and not wanting anyone to stare at me but having a job where that was part of it."

Related: Why HBO's 'True Blood' Should Be Revived, Not Rebooted

Not even Paquin's bisexuality interfered with the success of their relationship because Paquin says "marriage is about love, not gender."

Now, Paquin and Moyer are co-producing Flack, where Parquin plays a publicist, through their production company CASM. There were rumors saying their marriage was failing and that working on Flack saved it, but they are completely false.

Paquin recently commented on fan's hopes of an on-screen reunion between her and Moyer in Flack.

"Look, we love working together but none of us knows anything about season 3," Paquin told Entertainment Weekly. "It's hard to predict any aspect of our business right now. So, if this is it, it's been beautiful.

"But if it's not, there would be a chance that he would be a client because we love working with our friends and family."

Paquin and Moyer are constantly working together on different projects so it's not impossible that the two could have an on-screen reunion in the future. Right now, they're in lockdown like the rest of us, which will be the true test of their marriage. Maybe they should binge True Blood, just not with the kids.

Next: 15 Surprising Facts About HBO's True Blood