Template Slot Label not working

[dinuone]

  <b-field horizontal :type="userData.first_name.class" :message="userData.first_name.message">
       <template slot="label">First Name <span class="has-text-danger">*</span></template>
           <b-input
                  v-model="userData.first_name"
                  icon="pencil"
                  placeholder="First Name"
                  name="first_name"
                  maxlength="50"
                />
   </b-field>