diff --git a/spring-web/src/main/java/org/springframework/web/util/UriComponentsBuilder.java b/spring-web/src/main/java/org/springframework/web/util/UriComponentsBuilder.java
index 39d689be6724..f814955fe2b3 100644
--- a/spring-web/src/main/java/org/springframework/web/util/UriComponentsBuilder.java
+++ b/spring-web/src/main/java/org/springframework/web/util/UriComponentsBuilder.java
@@ -85,7 +85,7 @@ public class UriComponentsBuilder implements UriBuilder, Cloneable {
 
 	private static final String HOST_PATTERN = "(" + HOST_IPV6_PATTERN + "|" + HOST_IPV4_PATTERN + ")";
 
-	private static final String PORT_PATTERN = "([^/?#]*)";
+	private static final String PORT_PATTERN = "(\\{[^}]+}?|[^/?#]*)";
 
 	private static final String PATH_PATTERN = "([^?#]*)";
 
diff --git a/spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java b/spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java
index 2da0fc9b2857..3b8a5168cfb2 100644
--- a/spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java
+++ b/spring-web/src/test/java/org/springframework/web/util/UriComponentsBuilderTests.java
@@ -1297,4 +1297,14 @@ void verifyInvalidPort() {
 				.isInstanceOf(NumberFormatException.class);
 	}
 
+	@Test // gh-27039
+	void expandPortAndPathWithoutSeparator() {
+		URI uri = UriComponentsBuilder
+				.fromUriString("ws://localhost:{port}{path}")
+				.buildAndExpand(7777, "/test")
+				.toUri();
+		assertThat(uri.toString()).isEqualTo("ws://localhost:7777/test");
+	}
+
+
 }