Adding Minutes/Seconds to SMPTE Timecode

Hello Guys,

First post, but have used your helpful forum many times before to find answers!

I'm a little stuck with this one, and i'm reaching out for help!

I am trying to calculate a Final Timecode Value, for the end of a track.

In cell A2, I have the starting timecode value, formatted as text in the style of HH:MM:SS:FF
In Cell B2, I have audio track length, formatted as MM:SS
In Cell C2, I would like the final Timecode End Value...
Currently all timecode is 25fps, so no requirement to change that or account for that changing just yet...

So for example:

01:10:00:19 | 02:09 | 01:12:09:19
01:20:00:15 | 01:33 | 01:21:33:15

Is what i'd be after...

Any help would be amazing, would be willing to split cells, then concatenate etc if required, then hide cells etc... anything just to get this thing working!!