diff --git a/extensions/amp-slikeplayer/0.1/amp-slikeplayer.js b/extensions/amp-slikeplayer/0.1/amp-slikeplayer.js
index 028cb4e9cad9..37613a05fb71 100644
--- a/extensions/amp-slikeplayer/0.1/amp-slikeplayer.js
+++ b/extensions/amp-slikeplayer/0.1/amp-slikeplayer.js
@@ -1,5 +1,10 @@
 import {Deferred} from '#core/data-structures/promise';
 import {dispatchCustomEvent} from '#core/dom';
+import {
+  fullscreenEnter,
+  fullscreenExit,
+  isFullscreenElement,
+} from '#core/dom/fullscreen';
 import {isLayoutSizeDefined} from '#core/dom/layout';
 import {observeIntersections} from '#core/dom/layout/viewport-observer';
 import {once} from '#core/types/function';
@@ -8,7 +13,7 @@ import {Services} from '#service';
 import {installVideoManagerForDoc} from '#service/video-manager-impl';
 
 import {getData, listen} from '#utils/event-helper';
-import {userAssert} from '#utils/log';
+import {dev, userAssert} from '#utils/log';
 
 import {getConsentDataToForward} from '../../../src/consent';
 import {disableScrollingOnIframe} from '../../../src/iframe-helper';
@@ -87,6 +92,9 @@ export class AmpSlikeplayer extends AMP.BaseElement {
     /** @private {string} */
     this.baseUrl_ = 'https://tvid.in/player/amp.html';
 
+    /** @private {string} Origin of the player iframe; target for postMessage. */
+    this.targetOrigin_ = '*';
+
     /** @private {number} */
     this.duration_ = 1;
 
@@ -127,6 +135,16 @@ export class AmpSlikeplayer extends AMP.BaseElement {
     this.config_ = element.getAttribute('data-config') || '';
     this.poster_ = element.getAttribute('poster') || '';
 
+    // Resolve the player origin so messages target it explicitly rather than '*'.
+    try {
+      this.targetOrigin_ = new URL(
+        this.baseUrl_,
+        this.win.location.href
+      ).origin;
+    } catch {
+      this.targetOrigin_ = '*';
+    }
+
     // Read optional viewport visibility threshold from data-config
     if (this.config_) {
       try {
@@ -181,10 +199,10 @@ export class AmpSlikeplayer extends AMP.BaseElement {
 
   /** @override */
   layoutCallback() {
-    let src = `${this.baseUrl_}#apikey=${this.apikey_}&videoid=${this.videoid_}&baseurl=${this.win.location.origin}`;
+    let src = `${this.baseUrl_}#apikey=${this.apikey_}&videoid=${this.videoid_}&amp=1&baseurl=${this.win.location.origin}`;
 
     if (this.config_) {
-      src = `${this.baseUrl_}#apikey=${this.apikey_}&videoid=${this.videoid_}&${this.config_}&baseurl=${this.win.location.origin}`;
+      src = `${this.baseUrl_}#apikey=${this.apikey_}&videoid=${this.videoid_}&${this.config_}&amp=1&baseurl=${this.win.location.origin}`;
     }
 
     const frame = disableScrollingOnIframe(
@@ -241,6 +259,40 @@ export class AmpSlikeplayer extends AMP.BaseElement {
     return false;
   }
 
+  /** @override */
+  fullscreenEnter() {
+    if (!this.iframe_) {
+      return;
+    }
+    fullscreenEnter(dev().assertElement(this.iframe_));
+  }
+
+  /** @override */
+  fullscreenExit() {
+    if (!this.iframe_) {
+      return;
+    }
+    fullscreenExit(dev().assertElement(this.iframe_));
+  }
+
+  /** @override */
+  isFullscreen() {
+    if (!this.iframe_) {
+      return false;
+    }
+    return isFullscreenElement(dev().assertElement(this.iframe_));
+  }
+
+  /** @override */
+  showControls() {
+    this.postMessage_('showControls', '');
+  }
+
+  /** @override */
+  hideControls() {
+    this.postMessage_('hideControls', '');
+  }
+
   /** @private */
   onReady_() {
     const {element} = this;
@@ -261,6 +313,15 @@ export class AmpSlikeplayer extends AMP.BaseElement {
       return;
     }
 
+    // Defense-in-depth: ignore messages from an unexpected origin when known.
+    if (
+      this.targetOrigin_ !== '*' &&
+      messageEvent.origin &&
+      messageEvent.origin !== this.targetOrigin_
+    ) {
+      return;
+    }
+
     const messageData = getData(messageEvent);
     if (!isJsonOrObj(messageData)) {
       return;
@@ -290,6 +351,9 @@ export class AmpSlikeplayer extends AMP.BaseElement {
         case 'fullscreen':
           break;
         case 'meta':
+          if (detail.duration) {
+            this.duration_ = detail.duration;
+          }
           break;
         case 'mute':
           break;
@@ -298,6 +362,9 @@ export class AmpSlikeplayer extends AMP.BaseElement {
         case 'time':
           const {currentTime} = detail;
           this.currentTime_ = currentTime;
+          if (detail.duration) {
+            this.duration_ = detail.duration;
+          }
           break;
         case 'adTime':
           const {position} = detail;
@@ -429,7 +496,7 @@ export class AmpSlikeplayer extends AMP.BaseElement {
           'method': method,
           'optParams': optParams,
         }),
-        '*'
+        this.targetOrigin_
       );
     });
   }
diff --git a/extensions/amp-slikeplayer/0.1/test/test-amp-slikeplayer.js b/extensions/amp-slikeplayer/0.1/test/test-amp-slikeplayer.js
index 44384b3f696e..57d15b730957 100644
--- a/extensions/amp-slikeplayer/0.1/test/test-amp-slikeplayer.js
+++ b/extensions/amp-slikeplayer/0.1/test/test-amp-slikeplayer.js
@@ -77,6 +77,25 @@ describes.realWin(
       expect(src).to.contain('viewport=50');
     });
 
+    it('adds amp=1 to iframe src with and without data-config', async () => {
+      const {el: noConfig} = await buildPlayer({
+        'data-apikey': 'a',
+        'data-videoid': 'b',
+      });
+      expect(noConfig.querySelector('iframe').getAttribute('src')).to.contain(
+        'amp=1'
+      );
+
+      const {el: withConfig} = await buildPlayer({
+        'data-apikey': 'a',
+        'data-videoid': 'b',
+        'data-config': 'autoplay=true',
+      });
+      expect(withConfig.querySelector('iframe').getAttribute('src')).to.contain(
+        'amp=1'
+      );
+    });
+
     it('parses viewport threshold from percent and ratio', async () => {
       const {impl: implPct} = await buildPlayer({
         'data-config': 'viewport=150',
@@ -214,6 +233,78 @@ describes.realWin(
       await el.layoutCallback();
     });
 
+    it('fullscreenEnter/Exit delegate to the iframe, guarded by null', async () => {
+      const {iframe, impl} = await buildPlayer();
+      const enterSpy = (iframe.requestFullscreen = env.sandbox.spy());
+      const exitSpy = (iframe.exitFullscreen = env.sandbox.spy());
+
+      impl.fullscreenEnter();
+      expect(enterSpy).to.have.been.calledOnce;
+
+      impl.fullscreenExit();
+      expect(exitSpy).to.have.been.calledOnce;
+
+      // No iframe: methods are no-ops and must not throw.
+      impl.iframe_ = null;
+      expect(() => impl.fullscreenEnter()).to.not.throw();
+      expect(() => impl.fullscreenExit()).to.not.throw();
+    });
+
+    it('isFullscreen returns false without an iframe and by default', async () => {
+      const {impl} = await buildPlayer();
+      expect(impl.isFullscreen()).to.be.false;
+      impl.iframe_ = null;
+      expect(impl.isFullscreen()).to.be.false;
+    });
+
+    it('showControls/hideControls post the matching methods', async () => {
+      const {impl} = await buildPlayer();
+      const postSpy = env.sandbox.spy(impl, 'postMessage_');
+      impl.showControls();
+      impl.hideControls();
+      await Promise.resolve();
+      const methods = postSpy.getCalls().map((c) => c.args[0]);
+      expect(methods).to.include('showControls');
+      expect(methods).to.include('hideControls');
+    });
+
+    it('updates duration from meta and time events', async () => {
+      const {iframe, impl} = await buildPlayer();
+      impl.onMessage_({
+        source: iframe.contentWindow,
+        data: JSON.stringify({event: 'meta', detail: {duration: 120}}),
+      });
+      expect(impl.getDuration()).to.equal(120);
+
+      impl.onMessage_({
+        source: iframe.contentWindow,
+        data: JSON.stringify({
+          event: 'time',
+          detail: {currentTime: 5, duration: 200},
+        }),
+      });
+      expect(impl.getDuration()).to.equal(200);
+    });
+
+    it('ignores messages from an unexpected origin', async () => {
+      const {iframe, impl} = await buildPlayer();
+      const initial = impl.getCurrentTime();
+      impl.onMessage_({
+        source: iframe.contentWindow,
+        origin: 'https://evil.example.com',
+        data: JSON.stringify({event: 'time', detail: {currentTime: 77}}),
+      });
+      expect(impl.getCurrentTime()).to.equal(initial);
+
+      // Matching origin is accepted.
+      impl.onMessage_({
+        source: iframe.contentWindow,
+        origin: 'https://tvid.in',
+        data: JSON.stringify({event: 'time', detail: {currentTime: 88}}),
+      });
+      expect(impl.getCurrentTime()).to.equal(88);
+    });
+
     it('calls sendConsentData_ on send-consent-data message', async () => {
       const consentData = {
         consentPolicyState: 1,