NHibernate One-To-One Mapping

I'm new to NHibernate so have had limited exposure to mappings etc so far, and I've just hit a scenario which I need some help with.

I have 2 tables:

Reviews TaggedReviews

I have 2 classes that look like this (I've excluded non-important properties for brevity):

Review

public virtual int ReviewId { get; set; }
public virtual TaggedReview TaggedReview { get; set; }
public virtual string Title { get; set; }
public virtual string Descrip { get; set; }

TaggedReview

public virtual int ReviewId { get; set; }
public virtual Review Review { get; set; }
public virtual string TaggedReviewDescrip { get; set; }

My NHibernate XML mapping files for these tables/classes are currently as follows (edited for brevity):

Review.hbm.xml

<class xmlns="urn:nhibernate-mapping-2.2" name="Review" table="Reviews">
    <id name="ReviewId" unsaved-value="0">
        <column name="ReviewId"></column>
        <generator class="native" />
    </id>

    <property name="Title" not-null="true" />
    <property name="Descrip" not-null="true" />
    <one-to-one name="TaggedReview" class="TaggedReview" /> <!-- This is probably very wrong?! -->
</class>

TaggedReview.hbm.xml

<class xmlns="urn:nhibernate-mapping-2.2" name="TaggedReview" table="TaggedReviews">
    <id name="ReviewId">
        <column name="ReviewId"></column>
        <generator class="native"/>
    </id>
    <one-to-one name="Review" class="Review" /> <!-- This is probably very wrong?! -->
    <property name="TaggedReviewDescrip" not-null="true" />
</class>

The property 'ReviewId' is the PK for the 'Reviews' table. It's a FK in the 'TaggedReviews' table.

There is ALWAYS 1 record/row in the TaggedReviews table for every recor