The 'Roar' hitmaker and her musician friend - who were first romantically linked at the Coachella Valley Music and Arts festival earlier this month - were spotted enjoying an intimate meal at the Marlton Hotel in New York City on Thursday (24.04.14), before heading to the 'Amazing Spider-Man 2' after-party at Skylight at Moynihan Station, where they were ''very affectionate'' with one another.
A source said: ''They were very affectionate, very lovey-dovey.
''[When they weren't all over each other, they were constantly looking at each other.''
However, the pair ensured they weren't pictured together as they left the bash.
The source added to People: ''As they departed, they quickly separated. She didn't want it to look like they were together, but they were.''
The following evening, Katy - who was previously married to Russell Brand and split from John Mayer earlier this year after 18 months of dating - attended a birthday party at 1Oak, where Diplo was performing.
While the 'Part of Me' hitmaker seems smitten with the producer, friends are worried the romance could lead to her getting hurt again.
One worried pal told the Daily Mirror newspaper: ''Diplo always has girls throwing themselves at him, and it's fair to say he has his fun partying with them.
''But he's also got a three-year-old son with his on-off girlfriend that he doesn't see that often as he's on tour a lot.
''He also had a public fallout with his other ex, MIA, who he dated for five years, so Katy's friends are worried she could end up getting hurt - again - by a guy who's seen as a bit of a lothario.''
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