EmberJS, String interpolation in a helper call

I have this helper call in my template:

{{my-helper id='myID'}}

And I want to make the id param value a bit more dynamic, for example:

{{#each charts as |chart|}}
  {{my-helper id='chart' + chart.id}}
{{/each}}

How I can I use string interpolation and concatenation to create a value for a param in a helper call?