Is there an example of a star that is already dead, but can still be seen on Earth? While looking up at the stars I wondered, what are the odds that some of them are already dead. I did some research and found a very interesting article here. It states that the odds are rather small, so it is not like about 50% of the stars we see are already dead.

But I still wonder if there is an example of a star we know to be already gone, while it is still visible on earth.

As far as I know, the only way to find out is to watch the stars light. So if the light "goes out", we know the star has been gone for quite some time. Assuming this to be fact, I would have to conclude that such an example does not (and cannot) exist.

Is this true? Or is there in fact a star that is already dead that we know of, which can be seen in the sky?

PS: By "seeing the star" I am talking about a star that looks just like any other star in the night sky (not, for instance, a visible supernova).

Edit: If there is such a star, how did we find out it is already gone?
There is an accepted answer already, but there is a couple known cases of a star we know has gone supernova, and yet we can still see it.  This source describes one such unique circumstance.  The star that exploded happened to be in a galaxy that was behind another massive one from our point of view.  The alignment was just right such that the light formed an Einstein Cross.  The light from each point on the cross takes a different path to get here, and each of those paths are different lengths.  Thus, the different points on the cross show the star at 4 different times in its final years.  The Space.com article I linked was written in 2015. Scientists first noticed the supernova in 2014, and each image of the supernova arrived within a year of when it was first noticed.  If I'm understanding that article correctly, as of now (2017) all of the images of that supernova show the supernova aftermath, and not the star beforehand.  However, there was a period of time where we could see the star both pre and post-supernova at the same time.

You imply in your question that you are focusing on stars within our own galaxy.  I don't know of any such situations of Einstein Cross events closer to home that let us do this.