Forecasting shaded confidence interval

I've modelled by data using an external tool and have calculated the future predictions along with my confidence interval. Below you can see prediction in the dotted yellow line and the upper and lower boundary in blue and purple respectively.

I'd like this interval to be shaded just like the example below. I understand that there is a forecasting feature in the line chart in Power BI, which is how the below was created, but that calculates the forecast for you and provides its own confidence interval.

I've already calculated these myself but just want the same design as below to have the area shaded.

Does anyone know how/if this can be done?

Many thanks!

afk