Quite a common question on here actually. It's Datura stramonium (Thorn Apple). It's an annual weedy plant though the flowers are not unattractive. It's also very poisonous so wash you hands after touching it!

It's related to potatoes, tomatoes and Capsicum peppers though as said, its at the opposite end of the edibility scale :-)

Thanks very much and thanks for the warning! I'll be a lot more careful around it now.

It must be the weather! I've never seen one of these in real life, but people post pics and ask this question every few days. Perhaps it's been just right for it this freaky summer?

I've never seen one in real life either Beattie

It probably liked that hot, dry period in the south. A close relative is one of the few wildflowers that blooms in the summer, here.