professionally she goes really deep method, mainly because she's insecure about her lack of dramatic training. i can imagine that on set they'd keep a friendly distance between each other because of the nature of the script. personally, though, she tends to be very affable and friendly, though flighty and aloof; while they may have crafted a friendship on the press/festival circuit, she would have distanced herself afterward; some people read that as fakeness but it's in large part it's just her awkwardness and insecurity