diff --git a/hibernate-core/src/main/java/org/hibernate/metamodel/internal/MetadataContext.java b/hibernate-core/src/main/java/org/hibernate/metamodel/internal/MetadataContext.java
index 02276925acb5..e3a60f0a0e23 100644
--- a/hibernate-core/src/main/java/org/hibernate/metamodel/internal/MetadataContext.java
+++ b/hibernate-core/src/main/java/org/hibernate/metamodel/internal/MetadataContext.java
@@ -16,6 +16,7 @@
 import org.hibernate.boot.spi.MetadataImplementor;
 import org.hibernate.internal.CoreLogging;
 import org.hibernate.internal.CoreMessageLogger;
+import org.hibernate.internal.util.collections.ArrayHelper;
 import org.hibernate.internal.util.collections.CollectionHelper;
 import org.hibernate.mapping.Component;
 import org.hibernate.mapping.MappedSuperclass;
@@ -350,11 +351,17 @@ else if ( MappedSuperclass.class.isAssignableFrom( mapping.getClass() ) ) {
 //					applyNaturalIdAttribute( safeMapping, jpaType );
 
 					for ( Property property : safeMapping.getDeclaredProperties() ) {
-						if ( !safeMapping.isVersioned()
-								// skip the version property, it was already handled previously.
-								|| property != safeMapping.getVersion() ) {
-							buildAttribute( property, jpaType );
+						if ( isIdentifierProperty( property, safeMapping ) ) {
+							// property represents special handling for id-class mappings but we have already
+							// accounted for the embedded property mappings in #applyIdMetadata &&
+							// #buildIdClassAttributes
+							continue;
+						}
+						if ( safeMapping.isVersioned() && property == safeMapping.getVersion() ) {
+							// skip the version property, it was already handled previously.
+							continue;
 						}
+						buildAttribute( property, jpaType );
 					}
 
 					( (AttributeContainer<?>) jpaType ).getInFlightAccess().finishUp();
@@ -406,6 +413,12 @@ else if ( MappedSuperclass.class.isAssignableFrom( mapping.getClass() ) ) {
 		}
 	}
 
+	private static boolean isIdentifierProperty(Property property, MappedSuperclass mappedSuperclass) {
+		final Component identifierMapper = mappedSuperclass.getIdentifierMapper();
+		return identifierMapper != null ?
+				ArrayHelper.contains( identifierMapper.getPropertyNames(), property.getName() ) : false;
+	}
+
 	private <T> void addAttribute(EmbeddableDomainType<T> embeddable, Property property, Component component) {
 		final PersistentAttribute<T, ?> attribute =
 				attributeFactory.buildAttribute( embeddable, property);
diff --git a/hibernate-core/src/test/java/org/hibernate/orm/test/idclass/BaseSummary.java b/hibernate-core/src/test/java/org/hibernate/orm/test/idclass/BaseSummary.java
new file mode 100644
index 000000000000..03f409ca011f
--- /dev/null
+++ b/hibernate-core/src/test/java/org/hibernate/orm/test/idclass/BaseSummary.java
@@ -0,0 +1,62 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.idclass;
+
+import jakarta.persistence.Id;
+import jakarta.persistence.IdClass;
+import jakarta.persistence.MappedSuperclass;
+
+import java.io.Serializable;
+import java.math.BigDecimal;
+import java.util.Objects;
+
+@IdClass(PKey.class)
+@MappedSuperclass
+public class BaseSummary implements Serializable {
+
+	@Id
+	private Integer year;
+	@Id
+	private Integer month;
+	private BigDecimal value;
+
+	public Integer getYear() {
+		return year;
+	}
+
+	public void setYear(Integer year) {
+		this.year = year;
+	}
+
+	public Integer getMonth() {
+		return month;
+	}
+
+	public void setMonth(Integer month) {
+		this.month = month;
+	}
+
+	public BigDecimal getValue() {
+		return value;
+	}
+
+	public void setValue(BigDecimal value) {
+		this.value = value;
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if ( o == null || getClass() != o.getClass() ) {
+			return false;
+		}
+		BaseSummary that = (BaseSummary) o;
+		return Objects.equals( year, that.year ) && Objects.equals( month, that.month );
+	}
+
+	@Override
+	public int hashCode() {
+		return Objects.hash( year, month );
+	}
+}
diff --git a/hibernate-core/src/test/java/org/hibernate/orm/test/idclass/MappedSuperclassIdClassAttributesTest.java b/hibernate-core/src/test/java/org/hibernate/orm/test/idclass/MappedSuperclassIdClassAttributesTest.java
new file mode 100644
index 000000000000..d7d8738e2200
--- /dev/null
+++ b/hibernate-core/src/test/java/org/hibernate/orm/test/idclass/MappedSuperclassIdClassAttributesTest.java
@@ -0,0 +1,34 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.idclass;
+
+import jakarta.persistence.metamodel.SingularAttribute;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.JiraKey;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.Test;
+
+
+import static org.assertj.core.api.Assertions.assertThat;
+
+@DomainModel(annotatedClasses = {Summary.class, BaseSummary.class})
+@SessionFactory
+@JiraKey( "HHH-18858" )
+public class MappedSuperclassIdClassAttributesTest {
+
+	@Test
+	public void test(SessionFactoryScope scope) {
+		scope.inSession( entityManager -> {
+			final var yearAttribute = Summary_.year.getDeclaringType().getAttribute( "year" );
+			assertThat( yearAttribute ).isEqualTo( Summary_.year );
+			assertThat( ((SingularAttribute<?, ?>) yearAttribute).isId() ).isTrue();
+
+			final var monthAttribute = Summary_.month.getDeclaringType().getAttribute( "month" );
+			assertThat( monthAttribute ).isEqualTo( Summary_.month );
+			assertThat( ((SingularAttribute<?, ?>) monthAttribute).isId() ).isTrue();
+		} );
+	}
+}
diff --git a/hibernate-core/src/test/java/org/hibernate/orm/test/idclass/PKey.java b/hibernate-core/src/test/java/org/hibernate/orm/test/idclass/PKey.java
new file mode 100644
index 000000000000..5b4a8ea3b500
--- /dev/null
+++ b/hibernate-core/src/test/java/org/hibernate/orm/test/idclass/PKey.java
@@ -0,0 +1,44 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.idclass;
+
+import java.io.Serializable;
+import java.util.Objects;
+
+public class PKey implements Serializable {
+
+	private Integer year;
+	private Integer month;
+
+	public Integer getYear() {
+		return year;
+	}
+
+	public void setYear(Integer year) {
+		this.year = year;
+	}
+
+	public Integer getMonth() {
+		return month;
+	}
+
+	public void setMonth(Integer month) {
+		this.month = month;
+	}
+
+	@Override
+	public boolean equals(Object o) {
+		if ( o == null || getClass() != o.getClass() ) {
+			return false;
+		}
+		PKey pKey = (PKey) o;
+		return Objects.equals( year, pKey.year ) && Objects.equals( month, pKey.month );
+	}
+
+	@Override
+	public int hashCode() {
+		return Objects.hash( year, month );
+	}
+}
diff --git a/hibernate-core/src/test/java/org/hibernate/orm/test/idclass/Summary.java b/hibernate-core/src/test/java/org/hibernate/orm/test/idclass/Summary.java
new file mode 100644
index 000000000000..391717ad3835
--- /dev/null
+++ b/hibernate-core/src/test/java/org/hibernate/orm/test/idclass/Summary.java
@@ -0,0 +1,11 @@
+/*
+ * SPDX-License-Identifier: LGPL-2.1-or-later
+ * Copyright Red Hat Inc. and Hibernate Authors
+ */
+package org.hibernate.orm.test.idclass;
+
+import jakarta.persistence.Entity;
+
+@Entity
+public class Summary extends BaseSummary {
+}