They're at that level... with a capital "L."
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Katie, a source told the magazine, dropped the L-word during a phone call with her multi-talented man.
"She said she loved him," the source said. "She always gushes about how amazing he is and the joy he brings into the world."
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The couple has yet to formally or informally go public, but the magazine reported that Jamie is calling Katie "my girl." The two were first rumored to be together in late 2013.