The on-again, off-again couple, who also spent time in a Miami recording studio together last week, were spotted looking very cosy despite attempting to go unnoticed at the three-day event at the Empire Polo Club in Indio, California.
An eyewitness told UsMagazine.com that Selena, 21, cheered on Justin, 20, during his surprise performance with his friend Chance the Rapper on Sunday (13.04.14), and held hands with him as they made their way through an all-access area.
The insider added: ''They both had on sunglasses and had their heads down like they didn't want to be noticed.''
The duo were later seen slow dancing as they watched Calvin Harris' set, surrounded by four bodyguards.
Another source said: ''They were dancing slow right next to each other, swaying around. (They) were whispering to each other, laughing, [and] standing close together ... surrounded by four bodyguards backstage.''
The 'Come & Get It' hitmaker, who sought treatment in rehab in January after reportedly struggling to get over the Canadian singer, initially appeared to be enjoying a girls' trip to the annual festival, after arriving in the area with a group of pals, including Kendall and Kylie Jenner.
The brunette beauty and the 'Baby' singer - who have broken up several times since they first started dating in 2010 - have been keeping their fans guessing as to whether or not they are back together and have yet to comment on the current status of their relationship.
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