diff --git a/library/ui/src/main/java/com/google/android/exoplayer2/ui/SpannedToHtmlConverter.java b/library/ui/src/main/java/com/google/android/exoplayer2/ui/SpannedToHtmlConverter.java
index 532651e1d9..6aa0493dc4 100644
--- a/library/ui/src/main/java/com/google/android/exoplayer2/ui/SpannedToHtmlConverter.java
+++ b/library/ui/src/main/java/com/google/android/exoplayer2/ui/SpannedToHtmlConverter.java
@@ -26,6 +26,7 @@ import android.text.style.UnderlineSpan;
 import android.util.SparseArray;
 import androidx.annotation.ColorInt;
 import androidx.annotation.Nullable;
+import com.google.android.exoplayer2.text.span.HorizontalTextInVerticalContextSpan;
 import com.google.android.exoplayer2.text.span.RubySpan;
 import com.google.android.exoplayer2.util.Assertions;
 import com.google.android.exoplayer2.util.Util;
@@ -124,6 +125,8 @@ import java.util.regex.Pattern;
       ForegroundColorSpan colorSpan = (ForegroundColorSpan) span;
       return Util.formatInvariant(
           "<span style='color:%s;'>", toCssColor(colorSpan.getForegroundColor()));
+    } else if (span instanceof HorizontalTextInVerticalContextSpan) {
+      return "<span style='text-combine-upright:all;'>";
     } else if (span instanceof StyleSpan) {
       switch (((StyleSpan) span).getStyle()) {
         case Typeface.BOLD:
@@ -158,6 +161,8 @@ import java.util.regex.Pattern;
   private static String getClosingTag(Object span) {
     if (span instanceof ForegroundColorSpan) {
       return "</span>";
+    } else if (span instanceof HorizontalTextInVerticalContextSpan) {
+      return "</span>";
     } else if (span instanceof StyleSpan) {
       switch (((StyleSpan) span).getStyle()) {
         case Typeface.BOLD:
diff --git a/library/ui/src/test/java/com/google/android/exoplayer2/ui/SpannedToHtmlConverterTest.java b/library/ui/src/test/java/com/google/android/exoplayer2/ui/SpannedToHtmlConverterTest.java
index a69499296d..11eda1012e 100644
--- a/library/ui/src/test/java/com/google/android/exoplayer2/ui/SpannedToHtmlConverterTest.java
+++ b/library/ui/src/test/java/com/google/android/exoplayer2/ui/SpannedToHtmlConverterTest.java
@@ -26,6 +26,7 @@ import android.text.style.ForegroundColorSpan;
 import android.text.style.StyleSpan;
 import android.text.style.UnderlineSpan;
 import androidx.test.ext.junit.runners.AndroidJUnit4;
+import com.google.android.exoplayer2.text.span.HorizontalTextInVerticalContextSpan;
 import com.google.android.exoplayer2.text.span.RubySpan;
 import org.junit.Test;
 import org.junit.runner.RunWith;
@@ -49,6 +50,23 @@ public class SpannedToHtmlConverterTest {
         .isEqualTo("String with <span style='color:rgba(64,32,16,0.502);'>colored</span> section");
   }
 
+  @Test
+  public void convert_supportsHorizontalTextInVerticalContextSpan() {
+    SpannableString spanned = new SpannableString("Vertical text with 123 horizontal numbers");
+    spanned.setSpan(
+        new HorizontalTextInVerticalContextSpan(),
+        "Vertical text with ".length(),
+        "Vertical text with 123".length(),
+        Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
+
+    String html = SpannedToHtmlConverter.convert(spanned);
+
+    assertThat(html)
+        .isEqualTo(
+            "Vertical text with <span style='text-combine-upright:all;'>123</span> "
+                + "horizontal numbers");
+  }
+
   @Test
   public void convert_supportsStyleSpan() {
     SpannableString spanned =