Yup... As said, either is allowed... And if you make up a small bit of vanilla shake to use as creamer, it makes a lovely latte! Yum!
Worth remembering that normal full-caff coffee is a diuretic though, meaning you pee it put before your body can benefit from the water content... so that water doesn't really count towards your daily quota... So I stick with de-caff... But that's just coz I find the water hard to drink so need ways to make up my daily intake...
As LadyT says, make it with a whisk hunny... Make it first (just a small amount is needed) with some cold water, and mix it really well... then add the coffee and the boiling water... works a treat that way!