Repairing ornate post top (Damaged)

[pogo]

Hi,
I have a damaged post top. It used to sit one side of the gateway to my property until somone decided to try and pinch it only got round the corner and droped leaving behind broken. I have have finally got round to having a go at fixing It is made of concrete and I have a large chunk that has been broken off I have the part which will fit on but what can I use to attach. As I need a sort of glue to stick part back. Then I can repaint. Any help wil be great

 

[Aqua]

My first thought was plaster board adhesive to stick it back together, but also, if the broken part is large maybe drill both parts to allow a metal rod or two between them to give support.