Where in Macbeth does Lady Macbeth sleepwalk and talk?

The scene you want to look at is Act V scene 1, which
moves the action away from Macbeth and his approaching conflict with Malcolm and Macduff
for one moment to have a look at another human tragedy of the events of the play. The
Gentlewoman and Doctor that we are persented with discuss the condition of Lady Macbeth,
and then she is shown to enter, sleepwalking, making obvious reference in what she says
to her and her husband's involvement in the murder of
Duncan:

Yet
who would have thought the old man to have had so much blood in
him?

It is clear that this
amounts to a confession of her and her husband's murder of Duncan, yet at the same time
the way that she is acting speaks of the impact that her guilt has had upon her and how
she is plagued by the way that she abandoned herself to evil so quickly in Act I of the
play when she first heard of the prophecy of the witches.