According to eyewitnesses... Kim and Tom showed up to bid on a George Condo painting at the Reform Alliance Charity in Atlantic City, New Jersey, Saturday night.
We're told Kim kicked off the bidding at $500K, and then Tom put in a higher bid before they got into a full-on bidding war.
During their back and forth, the celebs giggled and kept looking at each other, and it was all "super fun and flirty," our sources tell us.
When the bid reached $2 million, the event hosts stepped in and decided both would receive their own George Condo painting.
But there was a caveat ... Kim and Tom each had to pay $2 million for their canvases, which for them is just chump change.
Meanwhile, Jay-Z, Michael Rubin and Meek Mill chaired the Reform Alliance’s Casino Night, which was aimed "to raise funds to transform probation and parole laws." Tickets for the gala event started at $500K.