Rob used to broadcast the news bulletins on BBC Radio Wales, but today it was his singing voice and songs which could be heard on the airwaves.
It was the first of two BBC Radio Wales' Sunday Celebration programmes recorded at Gateway Church in Abergavenny. The second service is due to be aired in April.
You can hear the today's service on BBC iPlayer featuring two of Rob's songs: Blessed Be and Thank You Jesus, here (for the a limited period):