Kristen Stewart has discussed her relationship with actor Robert Pattinson – describing their pairing as a “product”.

The Twilight co-stars began dating in 2008, before splitting in 2014, with the actress claiming the relationship became “not real life”. It’s not that I want to hide who I am or hide anything I’m doing in my life,” she added.

It's therefore pretty unsurprising that actors and actresses working on the same projects sometimes end up dating the same person. Way before she was twerking in a nude-colored thong all over an MTV podium, she dated the Jonas brother in 2006, before breaking up in 2007.

While it may happen more often than you might think, it never gets any less awkward. A year later and his new girlfriend was Selena, who he was with on-and-off until 2010. Ryan Phillippe Yep, it seems that there's something a bit incestuous going on within the Twilight cast.

Here are seven co-star pairings who broke all the rules and did the dirty with the same person. Lily Collins Taylor Lautner dated Lily Collins after meeting her on the set of Abduction in 2010. Before these two lovebirds broke all of our Bella and Edward hopes and dreams when they tragically split, Rob actually went on a blind date with artist Soko. On-screen sisters Nikki and Ashley were both involved with Ryan Phillippe.

Sadly, they split up just a week before the movie premiered, making for rather awkward interactions on the red carpet. Nikki in 2007, way before she married her husband Ian Somerhalder, and Ashley later in 2013.

Despite Robert Pattinson never having cheated on his then girlfriend, Stewart, in the traditional sense of the term, there always existed, a kind of enmity between Stewart and Reed, throughout the time that the “Twilight” saga was being shot.

Like, things are bound to get pretty weird if you’re hanging with the one person who used to be intimate with your ex, right?As their romance heats up (and their wedding date looms) we can look forward to many more outings for these two throughout the year.The actress has spoken out about the pressures of conforming to Hollywood ideals.At CFDA/Vogue Fashion Fund Show, earlier this week, Kristen Stewart ran into her old rival, Nikki Reed and all seemed to be forgiven and forgotten as they posed for a photo together for the thrilled shutterbugs!Nikki Reed flashed a polite half smile while Kristen Stewart kept it neutral with a carefree look.