It turns out the family feuding, which was caught on tape and released earlier this week, occurred on the night of Monday, May 5, because Jay-Z got a little too close with designer Rachel Roy, who's the ex-wife of his business partner Damon Dash.

"At the gala, Rachel was being flirtatious with Jay," a source exclusively tells E! News. "Once everyone was at the Boom Boom Room for the after-party, her flirtations were elevated."

Wendy Williams eluded to this earlier in the week on her show..