President Barack Obama's parting shot before leaving communist Vietnam was that his hosts should let people express themselves.
On Wednesday, he brought it up again during a light moment after providing a supporting beat to a female rapper who asked him a question at a town hall meeting with hundreds of young Vietnamese.
"Before I answer your question, why don't you give me a little rap? Let's see what you got," Mr Obama - his sky-blue shirt sleeves rolled up - told the rapper known as Suboi.
"Come on. Do you need like a little beat?" And he went on to show off his beat-boxing skills on the microphone.