And it involves Glee!!!
Watch (above) to get the scoop and then help us share the exciting news!!!!
But the former husband and wife didn't let that little fact stop them from celebrating a HUGE milestone in their son's life!
Sources say Guy and Madonna did not seem to harbor any animosity towards each other, and in fact they both only seemed to be looking proud - proud of their little boy who has just become a man!
We're so glad that these two can reunite for such a holy celebration. And we're sure Rocco appreciated it, too!
[Image via Doug Meszler / Splash News.]