vuejs2 – add letter to input with v-model

I need to add a letter in input always to begin with ‘&’ this input has v-model that not related to the data in v-model
so for example the input value will have to start always with & then some string that is coming from the v-model. the input might already has the & in the beginning and if not will have to be added
input has
value in the input needs to be : &hello

i tried to use value=’andText’ but it doesn’t seem to do the trick where andtext=’&’