1 of 29 Albert Ortega/WireImage.com
Stewart and Pattinson have been romantically linked since meeting on the set of Twilight in 2008, but neither would confirm nor deny the rumors for years.
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When they first met, Stewart was in relationship with her Speak co-star Michael Angarano, who's best known as Jack's son on Will & Grace. By early 2009, the couple had broken up.
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Stewart was cast first in Twilight and Pattinson had to film a screen test that included a kiss with her at director Catherine Hardwicke's house — on a bed. "MTV came and did an episode in my house filming the bed," Hardwicke later said. "It's legendary."
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Stewart pushed Hardwicke to cast Pattinson as Edward Cullen. "I basically cast him," she told Vanity Fair. "We did one day of auditions and a bunch of guys came in. Catherine Hardwicke, the director, afterwards was like, 'What do you think? This is such a hard choice.' I was like, 'Are you kidding me?! It's such an obvious choice!' It couldn't have been better. It was sort of perfect."
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The two kept a tight hold on each other at the world premiere of Twilight.
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Twilight hit theaters Nov. 21, 2008, and instantly became a blockbuster phenomenon. Reviews were mixed, but some singled out the chemistry between Pattinson and Stewart.
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Stewart and Pattinson, seen here with co-star Taylor Lautner, spend much quality time together during the huge publicity blitz for Twilight.
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The pair sent Twi-hards into a tizzy when they teased viewers by pretending to go in for a smooch while accepting their Best Kiss trophy at the 2009 MTV Movie Awards.
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The couple, seen here at the 2009 Comic-Con, continued to remain coy about the status of their relationship, but they were spotted out together that summer.
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Pattinson and Stewart stayed close at the 2009 Teen Choice Awards, where Twilight won nine of 12 nominations.
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In September 2009, Stewart and Pattinson, presenting here at the MTV Video Music Awards with Lautner, were rumored to be engaged. Neither commented on the report.
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In an interview with Entertainment Weekly in November 2009, Stewart said that she's tired of reporters asking her if she's dating Pattinson. "I probably would've answered it if people hadn't made such a big deal about it," she said. "But I'm not going to give the fiending an answer. I know that people are really funny about 'Well, you chose to be an actor, why don't you just f---ing give your whole life away?! Can I have your firstborn child?'"
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Actions speak louder than words. The pair's PDA grew incrementally more, well public, at events and they were even photographed walking hand-in-hand on an airport tarmac in November 2009.
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The Twilight Saga: New Moon was released Nov. 20, 2009, and set a slew of box office records, including the highest single-day domestic gross on opening day with $72.7 million until Harry Potter and the Deathly Hallows — Part 2 broke it in 2011.
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Stewart and Pattinson got cozy on the couch at Jimmy Kimmel Live while promoting New Moon with Lautner.
16 of 29 Jeff Kravitz/FilmMagic.com
No teasing this time. Pattinson and Stewart shared a quick peck at the 2010 MTV Movie Awards while picking up the Best Kiss popcorn.
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After a year of are-they-aren't-they, The Twilight Saga: Eclipse Wyck Godfrey confirmed to Time that the two are dating. "The thing that I think about is, 'Oh my God, I hope they stay together,'" he said. "Because it could be awkward on set in the next movie if they have a huge falling out. It's, like, 'Wow, they have to portray this love story through two more movies. God, I hope they stay together; please stay together.'"
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The Twilight Saga: Eclipse hit theaters June 30, 2010, and posted the biggest midnight opening ever with an estimated $30 million before Harry Potter and the Deathly Hallows — Part 2 surpassed it in 2011.
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It's no Brangelina or Bennifer, but K-Stew and R-Pattz eventually earned their own celebrity couple portmanteau: Robsten.
20 of 29 Jeff Kravitz/FilmMagic.com
The couple three-peat in the Best Kiss category at the 2011 MTV Movie Awards, but this time Pattinson had his eyes — and lips — on someone else: Lautner.
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Pattinson opened up about Stewart for the first time in the March 2011 issue of Vanity Fair. "It's just very traumatic," Pattinson said. "When [the Twilight saga] is over the media will lose interest [in the relationship]. There'll be nothing to say. It won't fit into a headline anymore. It won't fit into a template."
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Even if they don't stay together, their handprints will! Stewart and Pattison, along with Lautner, stick their hands and feet in cement alongside other iconic movie stars at the Grauman’s Chinese Theatre in November 2011.
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Who needs Brangelina when you have Robsten? Stewart shows some serious leg while linking with Pattinson at the Los Angeles premiere of The Twilight Saga: Breaking Dawn — Part 1.
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Stewart and Pattinson stay in sync, and linked, halfway across the world at the United Kingdom premiere of Breaking Dawn — Part 1.
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They have yet to say "I do" in real life, but Stewart and Pattinson got to play bride and groom on the set of Breaking Dawn — Part 1, when their characters, Bella and Edward, tied the knot.
26 of 29 Kevin Winter/Getty Images
Stewart and her Snow White and the Huntsman director, Rupert Sanders, don't just share an IMDb credit, they also seem to share fashion sense in similar white collared shirts and black blazers. Less than two months after this photo was taken, Stewart was photographed kissing Sanders, who is married and has two children.
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Stewart and Pattinson are all smiles with their future on-screen daughter, actress Mackenzie Foy, at Comic-Con in July 2012.
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Stewart and Pattinson were most recently photographed together at the 2012 Teen Choice Awards on July 22, 2012, just two days before accusations surfaced about her affair with her Snow White director Sanders. "This momentary indiscretion has jeopardized the most important thing in my life, the person I love and respect the most, Rob. I love him, I love him, I'm so sorry,” she said in a statement.
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The final film in the Twilight series, Breaking Dawn — Part 2 is set to hit theaters on Nov. 16, 2012. It’s unclear how Stewart’s indiscretion, and subsequently her rocky relationship with Pattinson, will affect the stars’ publicity duties for the film.