diff --git a/web/src/player/components/CircleButton.test.tsx b/web/src/player/components/CircleButton.test.tsx
new file mode 100644
index 00000000..f1d81657
--- /dev/null
+++ b/web/src/player/components/CircleButton.test.tsx
@@ -0,0 +1,36 @@
+import { describe, expect, it, vi } from "vitest";
+import { render, screen } from "@testing-library/react";
+import userEvent from "@testing-library/user-event";
+import { CircleButton } from "./CircleButton";
+
+describe("CircleButton", () => {
+  it("calls onClick when clicked", async () => {
+    const onClick = vi.fn();
+    render(
+      <CircleButton size="sm" variant="secondary" ariaLabel="Test" onClick={onClick}>
+        x
+      </CircleButton>,
+    );
+    await userEvent.click(screen.getByRole("button", { name: "Test" }));
+    expect(onClick).toHaveBeenCalledTimes(1);
+  });
+
+  it("applies the primary skin class for variant=primary", () => {
+    render(
+      <CircleButton size="md" variant="primary" ariaLabel="Play">
+        ▶
+      </CircleButton>,
+    );
+    const btn = screen.getByRole("button", { name: "Play" });
+    expect(btn.className).toContain("player-disc-primary");
+  });
+
+  it("sets data-paused when prop is true", () => {
+    render(
+      <CircleButton size="md" variant="primary" ariaLabel="Play" data-paused>
+        ▶
+      </CircleButton>,
+    );
+    expect(screen.getByRole("button")).toHaveAttribute("data-paused", "true");
+  });
+});
diff --git a/web/src/player/components/CircleButton.tsx b/web/src/player/components/CircleButton.tsx
new file mode 100644
index 00000000..9a0d0b51
--- /dev/null
+++ b/web/src/player/components/CircleButton.tsx
@@ -0,0 +1,48 @@
+export type CircleButtonProps = {
+  size: "sm" | "md" | "lg";
+  variant: "primary" | "secondary";
+  ariaLabel: string;
+  onClick?: () => void;
+  disabled?: boolean;
+  children: React.ReactNode;
+  "data-paused"?: boolean;
+};
+
+/**
+ * Glass-disc button used in both the video and audiobook player transports.
+ * - `primary` = glossy white disc (play/pause).
+ * - `secondary` = subtle glass disc (skip, prev/next).
+ * Sizes: `sm` 40–44px in-bar secondaries, `md` 52–56px in-bar play,
+ * `lg` 80px for floating variants (e.g. Now Listening play button).
+ */
+export function CircleButton({
+  size,
+  variant,
+  ariaLabel,
+  onClick,
+  disabled,
+  children,
+  "data-paused": dataPaused,
+}: CircleButtonProps) {
+  const base =
+    "flex items-center justify-center rounded-full focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-white/75 disabled:opacity-40 disabled:cursor-not-allowed";
+  const sizing =
+    size === "lg"
+      ? "h-20 w-20"
+      : size === "md"
+        ? "h-12 w-12 sm:h-14 sm:w-14"
+        : "h-10 w-10 sm:h-11 sm:w-11";
+  const skin = variant === "primary" ? "player-disc-primary" : "player-disc-secondary";
+  return (
+    <button
+      type="button"
+      aria-label={ariaLabel}
+      onClick={onClick}
+      disabled={disabled}
+      className={`${base} ${sizing} ${skin}`}
+      data-paused={dataPaused ? "true" : undefined}
+    >
+      {children}
+    </button>
+  );
+}
diff --git a/web/src/player/components/PlayerControls.tsx b/web/src/player/components/PlayerControls.tsx
index 6d224765..5d921592 100644
--- a/web/src/player/components/PlayerControls.tsx
+++ b/web/src/player/components/PlayerControls.tsx
@@ -10,6 +10,7 @@ import {
   SkipBack,
   SkipForward,
 } from "lucide-react";
+import { CircleButton } from "./CircleButton";
 import { SeekBar, formatTime } from "./SeekBar";
 import { VolumeControl } from "./VolumeControl";
 import { QualityMenu } from "./QualityMenu";
@@ -361,52 +362,6 @@ export function PlayerControls({
    Internal building blocks
    ───────────────────────────────────────────────────────────────────── */
 
-type CircleButtonProps = {
-  size: "sm" | "md" | "lg";
-  variant: "primary" | "secondary";
-  ariaLabel: string;
-  onClick?: () => void;
-  children: React.ReactNode;
-  "data-paused"?: boolean;
-};
-
-/**
- * Pill-circle button used in the centered playback cluster.
- * - `primary` = glossy white disc (play/pause).
- * - `secondary` = subtle glass disc (skip, prev/next episode).
- * Sizes: `sm` 40–44px for in-bar secondaries, `md` 52–56px for in-bar
- * play button, `lg` 80px reserved for a future floating variant.
- */
-function CircleButton({
-  size,
-  variant,
-  ariaLabel,
-  onClick,
-  children,
-  "data-paused": dataPaused,
-}: CircleButtonProps) {
-  const base =
-    "flex items-center justify-center rounded-full focus-visible:outline-none focus-visible:ring-2 focus-visible:ring-white/75";
-  const sizing =
-    size === "lg"
-      ? "h-20 w-20"
-      : size === "md"
-        ? "h-12 w-12 sm:h-14 sm:w-14"
-        : "h-10 w-10 sm:h-11 sm:w-11";
-  const skin = variant === "primary" ? "player-disc-primary" : "player-disc-secondary";
-  return (
-    <button
-      type="button"
-      aria-label={ariaLabel}
-      onClick={onClick}
-      className={`${base} ${sizing} ${skin}`}
-      data-paused={dataPaused ? "true" : undefined}
-    >
-      {children}
-    </button>
-  );
-}
-
 /** Invisible placeholder that reserves the exact footprint of a CircleButton
  *  so the playback cluster stays symmetric when a neighboring episode isn't
  *  available (first/last episode in a series). */