United Kingdom, April 3 -- Keke Palmer "knew something was wrong" when a stranger proposed because she could see the ring was "expensive".

The Nope actress was sitting on a Baby, This Is Keke Palmer Live panel at the SXSW Festival last month when a man from the audience got down on one knee to ask her to marry him and she could quickly tell it wasn't just a prank.

Speaking on the Decisions, Decisions podcast, she explained: "This is how I knew that something was wrong because the ring was nice. It wasn't like no Cracker Jack ring.

"I'm serious, the ring looked expensive. It looked expensive. That's when I knew something was up.

"That's when I was like 'is this a joke' because it was so sincere. I could see in his eyes that we've had r...