After calling off their engagement in 2012, Riley Keough and her ex-fiance Alex Pettyfer are spotted holding hands at the L.A. premiere of The Butler Credit: Theo Wargo/; Jason Merritt/Getty Images

Looks like Riley Keough can't help falling (back) in love with Alex Pettyfer. On Monday, Aug. 12, the 24-year-old actress -- granddaughter of the late Elvis Presley -- was spotted cozying up to her ex-fiance, Magic Mike actor Pettyfer, at the L.A. premiere screening of Lee Daniels' The Butler, hosted by Purity vodka and Fiji water.

"There was definitely warmth between Riley and Alex," an onlooker tells Us Weekly of the apparently on-again pair, who split last year. "They were laughing together and smiling at each other."

Another eyewitness notes that they were "holding hands" in the VIP area. "They definitely came together," the observer says, adding that Keough was wearing a ring on her left ring finger.

The stars -- who appeared together in Magic Mike -- first stepped out together in October 2011. Six months later, Lisa Marie Presley's daughter debuted an engagement ring from her British beau. "They have been inseparable since they started dating," an insider told Us at the time.

Before the year was up, though, the engagement was called off. Since then, Keough has been linked to Kristen Stewart's ex-boyfriend Robert Pattinson. As Us Weekly revealed earlier, the longtime pals were "hanging out and hooking up" for a while after the Twilight actor's breakup from his former costar.

"She's the first girl he's liked since Kristen," one insider told Us of Pattinson and Keough, who was in The Runaways with Stewart. "[They're] having a lot of fun."