The pair, who have both enjoyed high-profile spats with Taylor Swift , posed together as they helped Jennifer Lopez to celebrate her 47th birthday last night.
Scottish DJ Calvin couldn't resist a little smirk as he shared the lens with Kim at Caesar's Palace in Las Vegas.
Kim, dressed in a white mini dress with a plunging neckline, also flashed a knowing grin as she stood holding a lavish birthday cake.
The picture was shared to Instagram by rapper French Montana and fans couldn't help but giggle over the meeting.
"Bahahahaha Calvin and Kim!!! Yes!," one wrote.
"Kim K and Calvin Harris lol," another said.
"I bet Taylor Swift wasn't there," another added, with a crying laughing emoji.
A source told Us Weekly magazine: "Kim and Calvin did talk and interact, smiling and chatting for awhile."
All was very amicable between the pair until the Shake It Off star confirmed she penned his latest hit, This Is What You Came For.
Shortly after reps for the star confirmed she wrote the song under a pseudonym, Calvin slammed Taylor for 'trying to make him look bad' and told her to 'focus on her new relationship.
In a series of stinging tweets he fumed: "Hurtful to me at this point that her and her team would go so far out of their way to try and make ME look bad at this stage though.
"I know you're off tour and you need someone new to try and bury like Katy ETC but I'm not that guy, sorry. I won't allow it.
"Please focus on the positive aspects of YOUR life because you've earned a great one."
Meanwhile, Kim also sparked a public spat with the 26-year-oll singer last week when she exposed a video on Snapchat of her husband Kanye West talking to Taylor talking about his latest controversial track, 'Famous'.
The song includes the line: "I feel like me and Taylor might still have sex/ Why? I made that b**** famous."
Taylor has insisted she never gave her blessing over the song and has publicly slammed Kanye referring to her as a "b****".
But in the call she can be heard saying: "Go with whatever line you think is better. It's obviously very tongue in cheek either way. And I really appreciate you telling me about it, that's really nice!"
Taylor later said she was being painted as a "liar" and was never given the "full story" about the track.