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The couple celebrated the milestone Sunday with a cake that featured two red hearts and the message "1 Year" written on it. Harris, 32, revealed the dessert on Snapchat, saying in the video, "We got a one-year cake," as Swift, 26, nods in approval.
That's not all. On Instagram, Swift posted a photo of a golden locket, presumably a gift from Harris. She wrote, "3.6.15 One year down!"
Last July, Harris gushed about his relationship with the pop singer, telling Kiss FM UK, "It's going absolutely fantastic."