diff --git a/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/filter/headers/ForwardedHeadersFilter.java b/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/filter/headers/ForwardedHeadersFilter.java
index f5671412..d3941636 100644
--- a/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/filter/headers/ForwardedHeadersFilter.java
+++ b/spring-cloud-gateway-core/src/main/java/org/springframework/cloud/gateway/filter/headers/ForwardedHeadersFilter.java
@@ -25,7 +25,6 @@ import java.util.List;
 import java.util.Map;
 
 import org.jetbrains.annotations.Nullable;
-
 import org.springframework.core.Ordered;
 import org.springframework.http.HttpHeaders;
 import org.springframework.http.server.reactive.ServerHttpRequest;
@@ -58,7 +57,7 @@ public class ForwardedHeadersFilter implements HttpHeadersFilter, Ordered {
 		List<Forwarded> forwardeds = parse(original.get(FORWARDED_HEADER));
 
 		for (Forwarded f : forwardeds) {
-			updated.add(FORWARDED_HEADER, f.toString());
+			updated.add(FORWARDED_HEADER, f.toHeaderValue());
 		}
 
 		//TODO: add new forwarded
diff --git a/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/headers/ForwardedHeadersFilterTests.java b/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/headers/ForwardedHeadersFilterTests.java
index 21e343fa..dc1df9e3 100644
--- a/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/headers/ForwardedHeadersFilterTests.java
+++ b/spring-cloud-gateway-core/src/test/java/org/springframework/cloud/gateway/filter/headers/ForwardedHeadersFilterTests.java
@@ -17,23 +17,18 @@
 
 package org.springframework.cloud.gateway.filter.headers;
 
-import java.net.InetAddress;
-import java.net.InetSocketAddress;
-import java.net.UnknownHostException;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.HashMap;
-import java.util.List;
-import java.util.Map;
-
 import org.junit.Test;
-
 import org.springframework.cloud.gateway.filter.headers.ForwardedHeadersFilter.Forwarded;
 import org.springframework.http.HttpHeaders;
 import org.springframework.mock.http.server.reactive.MockServerHttpRequest;
 import org.springframework.mock.web.server.MockServerWebExchange;
 import org.springframework.util.StringUtils;
 
+import java.net.InetAddress;
+import java.net.InetSocketAddress;
+import java.net.UnknownHostException;
+import java.util.*;
+
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.springframework.cloud.gateway.filter.headers.ForwardedHeadersFilter.FORWARDED_HEADER;
 
@@ -67,6 +62,36 @@ public class ForwardedHeadersFilterTests {
 				.containsEntry("for", "\"10.0.0.1:80\"");
 	}
 
+	@Test
+	public void forwardedHeaderExists() throws UnknownHostException {
+		MockServerHttpRequest request = MockServerHttpRequest
+				.get("http://localhost/get")
+				.remoteAddress(new InetSocketAddress(InetAddress.getByName("10.0.0.1"), 80))
+				.header(FORWARDED_HEADER, "for=12.34.56.78;host=example.com;proto=https; for=23.45.67.89")
+				.build();
+
+		ForwardedHeadersFilter filter = new ForwardedHeadersFilter();
+
+		HttpHeaders headers = filter.filter(request.getHeaders(), MockServerWebExchange.from(request));
+
+		assertThat(headers.get(FORWARDED_HEADER)).hasSize(2);
+
+
+		List<Forwarded> forwardeds = ForwardedHeadersFilter.parse(headers.get(FORWARDED_HEADER));
+
+		assertThat(forwardeds).hasSize(2);
+		Forwarded addedForwardedHeader = forwardeds.get(0);
+		Forwarded existingForwardedHeader = forwardeds.get(1);
+
+		assertThat(existingForwardedHeader.getValues())
+				.containsEntry("proto", "http")
+				.containsEntry("for", "\"10.0.0.1:80\"");
+
+		assertThat(addedForwardedHeader.getValues())
+				.containsEntry("proto", "https")
+				.containsEntry("for", "23.45.67.89");
+	}
+
 	@Test
 	public void noHostHeader() throws UnknownHostException {
 		MockServerHttpRequest request = MockServerHttpRequest
@@ -92,7 +117,7 @@ public class ForwardedHeadersFilterTests {
 
 	@Test
 	public void forwardedParsedCorrectly() {
-		String[] valid = new String[] {
+		String[] valid = new String[]{
 				"for=\"_gazonk\"",
 				"for=192.0.2.60;proto=http;by=203.0.113.43",
 				"for=192.0.2.43, for=198.51.100.17",
@@ -103,15 +128,15 @@ public class ForwardedHeadersFilterTests {
 
 		@SuppressWarnings("unchecked")
 		List<List<Map<String, String>>> expectedFor = new ArrayList<List<Map<String, String>>>() {{
-				add(list(map("for", "\"_gazonk\"")));
-				add(list(map("for", "192.0.2.60", "proto", "http", "by", "203.0.113.43")));
-				add(list(map("for", "192.0.2.43"), map("for", "198.51.100.17")));
-				add(list(map("for", "12.34.56.78", "host", "example.com", "proto", "https"),
-						map("for", "23.45.67.89")));
-				add(list(map("for", "12.34.56.78"),
-						map("for", "23.45.67.89", "secret", "egah2CGj55fSJFs"),
-						map("for", "10.1.2.3")));
-				add(list(map("for", "\"[2001:db8:cafe::17]:4711\"")));
+			add(list(map("for", "\"_gazonk\"")));
+			add(list(map("for", "192.0.2.60", "proto", "http", "by", "203.0.113.43")));
+			add(list(map("for", "192.0.2.43"), map("for", "198.51.100.17")));
+			add(list(map("for", "12.34.56.78", "host", "example.com", "proto", "https"),
+					map("for", "23.45.67.89")));
+			add(list(map("for", "12.34.56.78"),
+					map("for", "23.45.67.89", "secret", "egah2CGj55fSJFs"),
+					map("for", "10.1.2.3")));
+			add(list(map("for", "\"[2001:db8:cafe::17]:4711\"")));
 		}};
 
 		for (int i = 0; i < valid.length; i++) {