Thank you for your question.
This is absolutely not a problem. In general, most TV's or monitors
have a "monitor" output that has both audio and video RCA connectors.
Simple connect the audio L and R to an aux input of your stereo
There will likely be a menu choice as well in the setup of the monitor
to select "Fixed" or "Variable" for the audio output for this
connection. Choose "Fixed"
Now, if by chance you meant truly connecting to a stereo Power
Amplifier, i.e., a power only amplifier that has no preamplifier built
in as you find in a Stereo Receiver, then you can choose the
"Variable" output and control the volume with the TV volume control.
In this case, you would want to disable the internal speakers, which
should be another menu choice.
Not knowing the specific model of your HDTV monitor, I can't direct
you further to which menus (assuming I could locate the manual for
your choice of make and model online), but they are usually available
under the category of Audio Setup. I did this for quite awhile before
I went surround sound and had quite pleasing results.
Now, just to be more sure of your intentions, I am also assuming you
will be using your standard stereo speakers and not trying to connect
your stereo receiver back to the speakers in the monitor. This likely
can not be done nor would it be recommended.
I realize this is a short answer to your question, but there isn't
much more that needs to be noted. Of course, as in connecting any
audio/video equipment, be sure power is off on all devices while
making your connections and have the volume controls down before
powering back up to be sure you do not get any rude surprises in case
the volume is more than expected from your usual volume settings.
Other than that, you should be good to go.
Do let me know if you need any further explanation.
None - years of playing with audio and video
If anything requires further explanations or research, please do post
a Request for Clarification prior to rating the answer and closing the
question and I will be pleased to assist further.