Yes. That's Himalayan Blackberry, aka Armenian blackberry. Probably seeded by a bird.

A common, aggressive weed in these parts. Remove it -- dig it out now-- while it's small..

If one lived in the PNW, Himalayan blackberry would be a very safe bet :-) It is EVERYWHERE and can be seeded everywhere, whereas domestic blackberries or even other, native blackberries tend to remain only where they are a) planted or b) prefer to grow. Himalayan blackberries have no such preferences and are not at all shy about popping up right about now where you are least inclined to want them.

They also look identical to that photo at this time of year.

Thanks, I will remove them before they overtook over the garden..

I removed this plant that came from nowhere and was going everywhere! I found that the roots were expanding through the area.

thanks for your comments!

Good luck!

Well done, Javier.

One of the best kinds of weeding I reckon is keeping a lookout for something that might not be a huge, whopping problem now but will be if it's ignored. Like seedling Blackberries.