diff --git a/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/common/EditInfo.java b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/common/EditInfo.java
index 9dc92a804e..46ef8796e4 100644
--- a/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/common/EditInfo.java
+++ b/gerrit-extension-api/src/main/java/com/google/gerrit/extensions/common/EditInfo.java
@@ -18,6 +18,7 @@ import java.util.Map;
 
 public class EditInfo {
   public CommitInfo commit;
+  public int basePatchSetNumber;
   public String baseRevision;
   public Map<String, FetchInfo> fetch;
   public Map<String, FileInfo> files;
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/edit/ChangeEditJson.java b/gerrit-server/src/main/java/com/google/gerrit/server/edit/ChangeEditJson.java
index 41af77d30e..78baef7195 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/edit/ChangeEditJson.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/edit/ChangeEditJson.java
@@ -51,6 +51,7 @@ public class ChangeEditJson {
     EditInfo out = new EditInfo();
     out.commit = fillCommit(edit.getEditCommit());
     out.baseRevision = edit.getBasePatchSet().getRevision().get();
+    out.basePatchSetNumber = edit.getBasePatchSet().getPatchSetId();
     if (downloadCommands) {
       out.fetch = fillFetchMap(edit);
     }