Let me preface this answer with:
Thank you. Now I have another plant on my garden wish list.
This beauty is a comparatively new cultivar of Hydrangea macrophylla with filled blooms.
They are also available as cut flowers, e.g. from here:
So yes, this is a real plant, not a silk replica.
This is a "silk", dried and dyed or otherwise replication of a Hydrangea.