Uncheck a checkbox when it is ng-disabled AngularJS

I have this dropdown with three roles:

1. Super Admin
2. Admin
3. User

And this checkbox that sets some extra privileges

• Give extra privileges.

What I want to achieve is this: When the User role is selected in the dropdown, the checkbox is BOTH disabled and unchecked. I have managed to disable it but if it has been checked beforehand, then it remains checked when disabled.

Here is my code:

$scope.model = {
    role: '',
    roles: ['Super Admin', 'Admin', 'User'],
    givePrivileges: false
}

HTML:

<md-input-container>
    <label>Role</label>
    <md-select ng-model="model.role">
        <md-option ng-repeat="role in model.roles" ng-value="role">
            
        </md-option>
    </md-select>
</md-input-container>
<md-input-container>
    <md-checkbox ng-disabled="model.role === 'User'">
        Give extra privileges
    </md-checkbox>
</md-input-container>