diff --git a/CHANGES.txt b/CHANGES.txt
index 549dd7eba8..188ce274b2 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -3,6 +3,7 @@
  * Do not go to disk for reading hints file sizes (CASSANDRA-19477)
  * Fix system_views.settings to handle array types (CASSANDRA-19475)
 Merged from 4.0:
+ * Fix CQL tojson timestamp output on negative timestamp values before Gregorian calendar reform in 1582 (CASSANDRA-19566)
  * Fix few types issues and implement types compatibility tests (CASSANDRA-19479)
  * Optionally avoid hint transfer during decommission (CASSANDRA-19525)
  * Change logging to TRACE when failing to get peer certificate (CASSANDRA-19508)
diff --git a/src/java/org/apache/cassandra/db/marshal/DateType.java b/src/java/org/apache/cassandra/db/marshal/DateType.java
index 473cedf407..372dac4f2c 100644
--- a/src/java/org/apache/cassandra/db/marshal/DateType.java
+++ b/src/java/org/apache/cassandra/db/marshal/DateType.java
@@ -80,7 +80,7 @@ public class DateType extends AbstractType<Date>
     @Override
     public String toJSONString(ByteBuffer buffer, ProtocolVersion protocolVersion)
     {
-        return '"' + TimestampSerializer.getJsonDateFormatter().format(TimestampSerializer.instance.deserialize(buffer)) + '"';
+        return '"' + TimestampSerializer.getJsonDateFormatter().format(TimestampSerializer.instance.deserialize(buffer).toInstant()) + '"';
     }
 
     @Override
diff --git a/src/java/org/apache/cassandra/db/marshal/TimestampType.java b/src/java/org/apache/cassandra/db/marshal/TimestampType.java
index ccf1da3e20..b11391e831 100644
--- a/src/java/org/apache/cassandra/db/marshal/TimestampType.java
+++ b/src/java/org/apache/cassandra/db/marshal/TimestampType.java
@@ -101,7 +101,7 @@ public class TimestampType extends TemporalType<Date>
 
     private String toString(Date date)
     {
-        return date != null ? TimestampSerializer.getJsonDateFormatter().format(date) : "";
+        return date != null ? TimestampSerializer.getJsonDateFormatter().format(date.toInstant()) : "";
     }
 
     @Override
diff --git a/src/java/org/apache/cassandra/serializers/TimestampSerializer.java b/src/java/org/apache/cassandra/serializers/TimestampSerializer.java
index 71782e5434..fcbfcc8537 100644
--- a/src/java/org/apache/cassandra/serializers/TimestampSerializer.java
+++ b/src/java/org/apache/cassandra/serializers/TimestampSerializer.java
@@ -22,7 +22,7 @@ import org.apache.cassandra.db.marshal.ValueAccessor;
 import org.apache.cassandra.utils.ByteBufferUtil;
 
 import java.nio.ByteBuffer;
-import java.text.SimpleDateFormat;
+import java.text.Format;
 import java.time.ZoneId;
 import java.time.ZonedDateTime;
 import java.time.format.DateTimeFormatter;
@@ -32,7 +32,6 @@ import java.time.temporal.ChronoField;
 import java.util.ArrayList;
 import java.util.Date;
 import java.util.List;
-import java.util.TimeZone;
 import java.util.regex.Pattern;
 
 import static org.apache.cassandra.utils.Clock.Global.currentTimeMillis;
@@ -105,23 +104,29 @@ public class TimestampSerializer extends TypeSerializer<Date>
 
     private static final Pattern timestampPattern = Pattern.compile("^-?\\d+$");
 
-    private static final FastThreadLocal<SimpleDateFormat> FORMATTER_UTC = new FastThreadLocal<SimpleDateFormat>()
+    private static final FastThreadLocal<Format> FORMATTER_UTC = new FastThreadLocal<Format>()
     {
-        protected SimpleDateFormat initialValue()
+        protected java.text.Format initialValue()
         {
-            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss.SSSX");
-            sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
-            return sdf;
+            return new DateTimeFormatterBuilder()
+                   .appendPattern("yyyy-MM-dd'T'HH:mm:ss.SSSX")
+                   .parseDefaulting(ChronoField.NANO_OF_DAY, 0)
+                   .toFormatter()
+                   .withZone(ZoneId.of("UTC"))
+                   .toFormat();
         }
     };
 
-    private static final FastThreadLocal<SimpleDateFormat> FORMATTER_TO_JSON = new FastThreadLocal<SimpleDateFormat>()
+    private static final FastThreadLocal<Format> FORMATTER_TO_JSON = new FastThreadLocal<Format>()
     {
-        protected SimpleDateFormat initialValue()
+        protected java.text.Format initialValue()
         {
-            SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss.SSSX");
-            sdf.setTimeZone(TimeZone.getTimeZone("UTC"));
-            return sdf;
+            return new DateTimeFormatterBuilder()
+                   .appendPattern("yyyy-MM-dd HH:mm:ss.SSSX")
+                   .parseDefaulting(ChronoField.NANO_OF_DAY, 0)
+                   .toFormatter()
+                   .withZone(ZoneId.of("UTC"))
+                   .toFormat();
         }
     };
 
@@ -171,7 +176,7 @@ public class TimestampSerializer extends TypeSerializer<Date>
         throw new MarshalException(String.format("Unable to parse a date/time from '%s'", source));
     }
 
-    public static SimpleDateFormat getJsonDateFormatter()
+    public static Format getJsonDateFormatter()
     {
     	return FORMATTER_TO_JSON.get();
     }
@@ -189,7 +194,7 @@ public class TimestampSerializer extends TypeSerializer<Date>
 
     public String toStringUTC(Date value)
     {
-        return value == null ? "" : FORMATTER_UTC.get().format(value);
+        return value == null ? "" : FORMATTER_UTC.get().format(value.toInstant());
     }
 
     public Class<Date> getType()
@@ -206,6 +211,6 @@ public class TimestampSerializer extends TypeSerializer<Date>
     {
         return buffer == null || !buffer.hasRemaining()
                ? "null"
-               : FORMATTER_UTC.get().format(deserialize(buffer));
+               : FORMATTER_UTC.get().format(deserialize(buffer).toInstant());
     }
 }