diff --git a/src/__tests__/prepare.test.js b/src/__tests__/prepare.test.js
index 66bd319..06ee50f 100644
--- a/src/__tests__/prepare.test.js
+++ b/src/__tests__/prepare.test.js
@@ -59,6 +59,17 @@ module TestGem
 end
 `);
   });
+
+  it('builds the gem', async () => {
+    const { gemFile } = await prepare(
+      {},
+      { ...context, nextRelease: { version: '1.0.0-alpha.1' } },
+      { versionFile, gemspec, gemName },
+    );
+
+    expect(gemFile).toEqual('a-test-gem-1.0.0.alpha.1.gem');
+    await expect(access(path.resolve(cwd, gemFile))).resolves.toBeUndefined();
+  });
 });
 
 describe('when updateGemfileLock is set to `true`', () => {
diff --git a/src/prepare.js b/src/prepare.js
index b3b9072..d2b64ef 100644
--- a/src/prepare.js
+++ b/src/prepare.js
@@ -4,16 +4,16 @@ const execa = require('execa');
 const { VERSION_REGEX } = require('./common');
 
 const writeVersion = async ({ versionFile, nextVersion, logger, cwd }) => {
+  // Rubygems replaces all `-` with `.pre.`, which causes odd version differences between tags/releases
+  // and the published gem version. Replacing `-` with `.` is a smaller difference.
+  const gemVersion = nextVersion.replace('-', '.');
   const fullVersionPath = path.resolve(cwd, versionFile);
   const versionContents = await readFile(fullVersionPath, 'utf8');
-  const newContents = versionContents.replace(
-    VERSION_REGEX,
-    // Rubygems replaces all `-` with `.pre.`, which causes odd version differences between tags/releases
-    // and the published gem version. Replacing `-` with `.` is a smaller difference.
-    `$1${nextVersion.replace('-', '.')}$2`,
-  );
+  const newContents = versionContents.replace(VERSION_REGEX, `$1${gemVersion}$2`);
   logger.log('Writing version %s to `%s`', nextVersion, versionFile);
   await writeFile(fullVersionPath, newContents, 'utf8');
+
+  return { gemVersion };
 };
 
 const bundleInstall = async ({ updateGemfileLock, cwd, env, logger, stdout, stderr }) => {
@@ -43,13 +43,22 @@ module.exports = async function prepare(
   { nextRelease: { version }, cwd, env, logger, stdout, stderr },
   { versionFile, gemspec, gemName },
 ) {
-  await writeVersion({ versionFile, nextVersion: version, logger, cwd });
+  const { gemVersion } = await writeVersion({ versionFile, nextVersion: version, logger, cwd });
 
   if (updateGemfileLock) {
     await bundleInstall({ updateGemfileLock, cwd, env, logger, stdout, stderr });
   }
 
-  const gemFile = await buildGem({ gemspec, gemName, version, cwd, env, logger, stdout, stderr });
+  const gemFile = await buildGem({
+    gemspec,
+    gemName,
+    version: gemVersion,
+    cwd,
+    env,
+    logger,
+    stdout,
+    stderr,
+  });
 
   return { gemFile };
 };