diff --git a/src/components/views/settings/KeyBackupPanel.js b/src/components/views/settings/KeyBackupPanel.js
index 67d2d32d50..f4740ea649 100644
--- a/src/components/views/settings/KeyBackupPanel.js
+++ b/src/components/views/settings/KeyBackupPanel.js
@@ -20,6 +20,7 @@ import sdk from '../../../index';
 import MatrixClientPeg from '../../../MatrixClientPeg';
 import { _t } from '../../../languageHandler';
 import Modal from '../../../Modal';
+import SettingsStore from '../../../../lib/settings/SettingsStore';
 
 export default class KeyBackupPanel extends React.PureComponent {
     constructor(props) {
@@ -124,6 +125,27 @@ export default class KeyBackupPanel extends React.PureComponent {
         );
     }
 
+    _bootstrapSecureSecretStorage = async () => {
+        try {
+            const InteractiveAuthDialog = sdk.getComponent("dialogs.InteractiveAuthDialog");
+            await MatrixClientPeg.get().bootstrapSecretStorage({
+                doInteractiveAuthFlow: async (makeRequest) => {
+                    const { finished } = Modal.createTrackedDialog(
+                        'Cross-signing keys dialog', '', InteractiveAuthDialog,
+                        {
+                            title: _t("Send cross-signing keys to homeserver"),
+                            matrixClient: MatrixClientPeg.get(),
+                            makeRequest,
+                        },
+                    );
+                    await finished;
+                },
+            });
+        } catch (e) {
+            console.error(e);
+        }
+    }
+
     _deleteBackup = () => {
         const QuestionDialog = sdk.getComponent('dialogs.QuestionDialog');
         Modal.createTrackedDialog('Delete Backup', '', QuestionDialog, {
@@ -298,6 +320,21 @@ export default class KeyBackupPanel extends React.PureComponent {
                 </div>
             </div>;
         } else {
+            // This is a temporary button for testing SSSS. Initialising SSSS
+            // depends on cross-signing and is part of the same project, so we
+            // only show this mode when the cross-signing feature is enabled.
+            // TODO: Clean this up when removing the feature flag.
+            let bootstrapSecureSecretStorage;
+            if (SettingsStore.isFeatureEnabled("feature_cross_signing")) {
+                bootstrapSecureSecretStorage = (
+                    <div className="mx_KeyBackupPanel_buttonRow">
+                        <AccessibleButton kind="primary" onClick={this._bootstrapSecureSecretStorage}>
+                            {_t("Bootstrap Secure Secret Storage (MSC1946)")}
+                        </AccessibleButton>
+                    </div>
+                );
+            }
+
             return <div>
                 <div>
                     <p>{_t(
@@ -307,9 +344,12 @@ export default class KeyBackupPanel extends React.PureComponent {
                     <p>{encryptedMessageAreEncrypted}</p>
                     <p>{_t("Back up your keys before signing out to avoid losing them.")}</p>
                 </div>
-                <AccessibleButton kind="primary" onClick={this._startNewBackup}>
-                    { _t("Start using Key Backup") }
-                </AccessibleButton>
+                <div className="mx_KeyBackupPanel_buttonRow">
+                    <AccessibleButton kind="primary" onClick={this._startNewBackup}>
+                        {_t("Start using Key Backup")}
+                    </AccessibleButton>
+                </div>
+                {bootstrapSecureSecretStorage}
             </div>;
         }
     }
diff --git a/src/i18n/strings/en_EN.json b/src/i18n/strings/en_EN.json
index c42a137800..e60007be5e 100644
--- a/src/i18n/strings/en_EN.json
+++ b/src/i18n/strings/en_EN.json
@@ -511,6 +511,7 @@
     "Connecting to integrations server...": "Connecting to integrations server...",
     "Cannot connect to integrations server": "Cannot connect to integrations server",
     "The integrations server is offline or it cannot reach your homeserver.": "The integrations server is offline or it cannot reach your homeserver.",
+    "Send cross-signing keys to homeserver": "Send cross-signing keys to homeserver",
     "Delete Backup": "Delete Backup",
     "Are you sure? You will lose your encrypted messages if your keys are not backed up properly.": "Are you sure? You will lose your encrypted messages if your keys are not backed up properly.",
     "Encrypted messages are secured with end-to-end encryption. Only you and the recipient(s) have the keys to read these messages.": "Encrypted messages are secured with end-to-end encryption. Only you and the recipient(s) have the keys to read these messages.",
@@ -533,6 +534,7 @@
     "This backup is trusted because it has been restored on this device": "This backup is trusted because it has been restored on this device",
     "Backup version: ": "Backup version: ",
     "Algorithm: ": "Algorithm: ",
+    "Bootstrap Secure Secret Storage (MSC1946)": "Bootstrap Secure Secret Storage (MSC1946)",
     "Your keys are <b>not being backed up from this device</b>.": "Your keys are <b>not being backed up from this device</b>.",
     "Back up your keys before signing out to avoid losing them.": "Back up your keys before signing out to avoid losing them.",
     "Start using Key Backup": "Start using Key Backup",