This is part of the Frank said feature. You can see more here.
We were making dinner the other night and as I was chopping something, I heard Frank singing quietly…
Frank: [singing quietly] And you’ll never be royal, royal, you can call me green bean…
Me: What did you say?
Frank: [sings again, but a little more loudly] You can call me green bean
Me: I think you mean, “queen bee”
Frank: No, its green bean. She sings it wrong.