Streaming from a Pi2 to Firestick…

Hi All,
I’m currently using a Firestick with Kodi on it to stream to my TV. Previously I was using a Pi2 with Kodi and an external hard drive as a sort of mini media centre. Since my TV only has 2 HDMI ports (one for the Sky box and one for the Firestick I was wondering if there was a way to stream the contents of the HDD that is connected to my Pi to my TV via the Firestick?
I’m quite new to this and didn’t set my Pi up myself (a former colleague set it up for me, so I just plugged it in), but I am getting more into the setup since I got the Firestick.

Thanks in advance,
Jamie.