It barely even sounds like Milkshake. Very minimalistic and pure genius. The lyrics speak for itself. I love her conversation with Pharell in the second (third?) verse.
I thought it was confirmed as the second single too, but Gwen recently said it's going to be the title track. Yummy will probably be the third single.
Monotone is the new melody.
1 LOVE, Until that day, Breakin' Up, Yummy, etc. etc.