Bobby, Apollonia and Mark Brown initially hula-hoop over grass (6)

I haven't cracked this one yet — but the brilliant team at Fifteensquared have:

B A M B (first or ‘initial’ letters of Bobby, Apollonia, Mark and Brown)+ O (hoola-hoop) O (over) – apparently Bobby Z was a drummer and Brown Mark was a bassist in the Revolution, and Apollonia Kotero is an actress who co-starred in Prince’s 1984 film 6d 4d