diff --git a/app/build.gradle b/app/build.gradle
index 1275b8e7a..5234c6ad1 100644
--- a/app/build.gradle
+++ b/app/build.gradle
@@ -231,7 +231,7 @@ android.applicationVariants.all { variant ->
 
     def isDebug = variant.buildType.resValues['IS_DEBUG']?.value ?: false
     def useReleaseVersioning = variant.buildType.buildConfigFields['USE_RELEASE_VERSIONING']?.value ?: false
-    def versionName = Config.releaseVersionName(project)
+    def versionName = variant.buildType.name == 'nightly' ? Config.nightlyVersionName() : Config.releaseVersionName(project)
 
     println("----------------------------------------------")
     println("Variant name:      " + variant.name)
@@ -245,6 +245,8 @@ android.applicationVariants.all { variant ->
         // same version code. Therefore we need to have different version codes for our ARM and x86
         // builds.
 
+        println("versionName override: $versionName")
+
         variant.outputs.each { output ->
             def abi = output.getFilter(OutputFile.ABI)
             // We use the same version code generator, that we inherited from Fennec, across all channels - even on
diff --git a/buildSrc/src/main/java/Config.kt b/buildSrc/src/main/java/Config.kt
index ff824ff74..7460906f4 100644
--- a/buildSrc/src/main/java/Config.kt
+++ b/buildSrc/src/main/java/Config.kt
@@ -36,6 +36,14 @@ object Config {
         return if (project.hasProperty("versionName")) project.property("versionName") as String else ""
     }
 
+    @JvmStatic
+    fun nightlyVersionName(): String {
+        // Nightly versions use the Gecko/A-C major version and append "0.a1", e.g. with A-C 90.0.20210426143115
+        // the Nightly version will be 90.0a1
+        val majorVersion = AndroidComponents.VERSION.split(".")[0]
+        return "$majorVersion.0a1"
+    }
+
     @JvmStatic
     fun generateBuildDate(): String {
         val dateTime = LocalDateTime.now()
diff --git a/taskcluster/fenix_taskgraph/transforms/build.py b/taskcluster/fenix_taskgraph/transforms/build.py
index 4a65b4abb..4c8029a69 100644
--- a/taskcluster/fenix_taskgraph/transforms/build.py
+++ b/taskcluster/fenix_taskgraph/transforms/build.py
@@ -95,14 +95,11 @@ def add_disable_optimization(config, tasks):
 
 @transforms.add
 def add_nightly_version(config, tasks):
-    push_date_string = config.params["moz_build_date"]
-    push_date_time = datetime.datetime.strptime(push_date_string, "%Y%m%d%H%M%S")
-    formated_date_time = 'Nightly {}'.format(push_date_time.strftime('%y%m%d %H:%M'))
-
     for task in tasks:
         if task.pop("include-nightly-version", False):
             task["run"]["gradlew"].extend([
-                '-PversionName={}'.format(formated_date_time),
+                # We only set the `official` flag here. The actual version name will be determined
+                # by Gradle (depending on the Gecko/A-C version being used)
                 '-Pofficial'
             ])
         yield task