Los Angeles, March 7-Singer Taylor Swift and her boyfriend DJ Calvin Harris celebrated their first anniversary together on Sunday. To mark the occasion, Harris gifted Swift a heart-shaped gold locket necklace, reports aceshowbiz.com. The "Wildest dream" singer took to Instagram to give fans a look at the locket engraved with the date "3.6 2015" on it. "3.6.15 One year down," Swift captioned the photograph. According to a source close to the couple, Harris chose the gift himself because he wanted to give Swift something meaningful. "He bought the locket all on his own. Calvin is not a flashy guy when it comes to gifts and he knows Taylor appreciates the small meaningful things, so he thought this would be the perfect gift," the insider revealed. Harris also gave some other surprises throughout the day, including a cake covered with chocolate with the words "1 Year" on it. "Taylor is a true hopeless romantic kind of lady and she thought Calvin really outdid himself with this gift," the source added. "He had surprises for Taylor all throughout the day."