Did young Riddle meet Grindelwald?

[Hagrid]

No: HPFGUIDX 156596

>From memory, JKR was evasive about saying anything about Grindelwald
in the interview straight after the release of HBP. What could be there?

I am wondering if the way Grindelwald treated Riddle was similar to
the way Voldemort treated Draco (ie: Draco had to AK DD and Riddle had
to AK Riddle Snr).

Of course, Riddle may not have met Grindelwald until after Hogwarts. 

What happened?
When?
Why?

aussie