diff --git a/schemas/src/elements/inlines/TextRun.json b/schemas/src/elements/inlines/TextRun.json
index ccf7595551..77e0834ab4 100644
--- a/schemas/src/elements/inlines/TextRun.json
+++ b/schemas/src/elements/inlines/TextRun.json
@@ -42,6 +42,14 @@
       "type": "boolean",
       "description": "If `true`, displays the text with strikethrough."
     },
+    "underline": {
+      "type": "boolean",
+      "description": "If `true`, displays the text with an underline.",
+      "version": "1.3",
+      "features": [
+        3051
+      ]
+    },
     "weight": {
       "type": "FontWeight",
       "description": "Controls the weight of the text."
diff --git a/specs/elements/TextRun.md b/specs/elements/TextRun.md
index b887057926..ed7e07e404 100644
--- a/specs/elements/TextRun.md
+++ b/specs/elements/TextRun.md
@@ -16,6 +16,7 @@
 | **selectAction** | `ISelectAction` | No | Action to invoke when this text run is clicked. Visually changes the text run into a hyperlink. `Action.ShowCard` is not supported. | 1.2 |
 | **size** | `FontSize` | No | Controls size of text. | 1.2 |
 | **strikethrough** | `boolean` | No | If `true`, displays the text with strikethrough. | 1.2 |
+| **underline** | `boolean` | No | If `true`, displays the text with an underline. | 1.3 |
 | **weight** | `FontWeight` | No | Controls the weight of the text. | 1.2 |