diff --git a/hibernate-core/src/test/java/org/hibernate/orm/test/annotations/cid/KeyToOneObjectIdentityTest.java b/hibernate-core/src/test/java/org/hibernate/orm/test/annotations/cid/KeyToOneObjectIdentityTest.java
new file mode 100644
index 000000000000..3973411a67f3
--- /dev/null
+++ b/hibernate-core/src/test/java/org/hibernate/orm/test/annotations/cid/KeyToOneObjectIdentityTest.java
@@ -0,0 +1,262 @@
+/*
+ * Hibernate, Relational Persistence for Idiomatic Java
+ *
+ * License: GNU Lesser General Public License (LGPL), version 2.1 or later
+ * See the lgpl.txt file in the root directory or http://www.gnu.org/licenses/lgpl-2.1.html
+ */
+package org.hibernate.orm.test.annotations.cid;
+
+import jakarta.persistence.Embeddable;
+import jakarta.persistence.EmbeddedId;
+import jakarta.persistence.Entity;
+import jakarta.persistence.FetchType;
+import jakarta.persistence.Id;
+import jakarta.persistence.ManyToOne;
+import jakarta.persistence.Table;
+import org.hibernate.testing.orm.junit.DomainModel;
+import org.hibernate.testing.orm.junit.Jira;
+import org.hibernate.testing.orm.junit.SessionFactory;
+import org.hibernate.testing.orm.junit.SessionFactoryScope;
+import org.junit.jupiter.api.Test;
+
+import java.math.BigDecimal;
+import java.util.Objects;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertNotNull;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+@DomainModel(
+		annotatedClasses = {
+				KeyToOneObjectIdentityTest.Customer.class,
+				KeyToOneObjectIdentityTest.Order.class,
+				KeyToOneObjectIdentityTest.LineItem.class,
+		}
+)
+@SessionFactory
+@Jira("https://hibernate.atlassian.net/browse/HHH-9579")
+public class KeyToOneObjectIdentityTest {
+
+	@Test
+	public void test(SessionFactoryScope scope) {
+		final String customerName = "customerName";
+		final String product = "The Special Box";
+		final String orderRef = "orderRef1234";
+		final int quantity = 42;
+
+		LineItem.Id lineItemId = scope.fromTransaction( s -> {
+			Customer customer = new Customer( 1L, customerName );
+			s.persist( customer );
+			Order order = new Order( 1L, customer, BigDecimal.ONE, orderRef );
+			s.persist( order );
+			LineItem lineItem = new LineItem( new LineItem.Id( order, 0 ) );
+			lineItem.setLineItemIndex( 0 );
+			lineItem.setProduct( product );
+			lineItem.setQuantity( quantity );
+			s.persist( lineItem );
+			return lineItem.getId();
+		} );
+
+		scope.getSessionFactory().getCache().evictAllRegions();
+		scope.inTransaction( s -> {
+			LineItem lineItem = s.get( LineItem.class, lineItemId );
+			assertNotNull( lineItem );
+			assertEquals( product, lineItem.getProduct() );
+			assertEquals( quantity, lineItem.getQuantity() );
+			assertTrue( s.contains( lineItem ) );
+			LineItem.Id id = lineItem.getId();
+			assertNotNull( id );
+
+			Order order = id.getOrder();
+			assertNotNull( order );
+			assertEquals( orderRef, order.getOrderRef() );
+			assertTrue( s.contains( order ) );
+
+			Customer customer = order.getCustomer();
+			assertNotNull( customer );
+			assertEquals( customerName, customer.getName() );
+			assertTrue( s.contains( customer ) );
+		} );
+	}
+
+	@Entity(name = "Customer")
+	public static class Customer {
+		@Id
+		private long customerId;
+		private String name;
+
+		public Customer() {
+		}
+
+		public Customer(long customerId, String name) {
+			this.customerId = customerId;
+			this.name = name;
+		}
+
+		public long getCustomerId() {
+			return customerId;
+		}
+
+		public void setCustomerId(long customerId) {
+			this.customerId = customerId;
+		}
+
+		public String getName() {
+			return name;
+		}
+
+		public void setName(String name) {
+			this.name = name;
+		}
+	}
+
+	@Entity(name = "Order")
+	@Table(name = "ord_tbl")
+	public static class Order {
+		@Id
+		private long orderId;
+		@ManyToOne(fetch = FetchType.LAZY)
+		private Customer customer;
+		private BigDecimal total;
+		private String orderRef;
+
+		public Order() {
+		}
+
+		public Order(long orderId, Customer customer, BigDecimal total, String orderRef) {
+			this.orderId = orderId;
+			this.customer = customer;
+			this.total = total;
+			this.orderRef = orderRef;
+		}
+
+		public long getOrderId() {
+			return orderId;
+		}
+
+		public void setOrderId(long orderId) {
+			this.orderId = orderId;
+		}
+
+		public Customer getCustomer() {
+			return customer;
+		}
+
+		public void setCustomer(Customer customer) {
+			this.customer = customer;
+		}
+
+		public BigDecimal getTotal() {
+			return total;
+		}
+
+		public void setTotal(BigDecimal total) {
+			this.total = total;
+		}
+
+		public String getOrderRef() {
+			return orderRef;
+		}
+
+		public void setOrderRef(String orderRef) {
+			this.orderRef = orderRef;
+		}
+	}
+
+	@Entity(name = "LineItem")
+	public static class LineItem {
+
+		@Embeddable
+		public static class Id {
+			@ManyToOne(fetch = FetchType.EAGER)
+			private Order order;
+			private int orderLineId;
+
+			public Id() {
+			}
+
+			public Id(Order order, int orderLineId) {
+				setOrder( order );
+				setOrderLineId( orderLineId );
+			}
+
+			public Order getOrder() {
+				return order;
+			}
+
+			public void setOrder(Order order) {
+				this.order = order;
+			}
+
+			public int getOrderLineId() {
+				return orderLineId;
+			}
+
+			public void setOrderLineId(int orderLineId) {
+				this.orderLineId = orderLineId;
+			}
+
+			@Override
+			public final boolean equals(Object o) {
+				if ( !( o instanceof Id id ) ) {
+					return false;
+				}
+
+				return orderLineId == id.orderLineId && Objects.equals( order, id.order );
+			}
+
+			@Override
+			public int hashCode() {
+				int result = Objects.hashCode( order );
+				result = 31 * result + orderLineId;
+				return result;
+			}
+		}
+
+		@EmbeddedId
+		private Id id = new Id();
+		private int lineItemIndex;
+		private int quantity;
+		//	private Order order;
+		private String product;
+
+		public LineItem(Id id) {
+			setId( id );
+		}
+
+		public LineItem() {
+		}
+
+		public Id getId() {
+			return id;
+		}
+
+		public void setId(Id id) {
+			this.id = id;
+		}
+
+		public int getLineItemIndex() {
+			return lineItemIndex;
+		}
+
+		public void setLineItemIndex(int lineItemIndex) {
+			this.lineItemIndex = lineItemIndex;
+		}
+
+		public int getQuantity() {
+			return quantity;
+		}
+
+		public void setQuantity(int quantity) {
+			this.quantity = quantity;
+		}
+
+		public String getProduct() {
+			return product;
+		}
+
+		public void setProduct(String product) {
+			this.product = product;
+		}
+	}
+}