diff --git a/akka-cluster-sharding/src/main/scala/akka/cluster/sharding/ClusterSharding.scala b/akka-cluster-sharding/src/main/scala/akka/cluster/sharding/ClusterSharding.scala
index 688c228ab0..3cf2a1deb1 100644
--- a/akka-cluster-sharding/src/main/scala/akka/cluster/sharding/ClusterSharding.scala
+++ b/akka-cluster-sharding/src/main/scala/akka/cluster/sharding/ClusterSharding.scala
@@ -5,13 +5,11 @@ package akka.cluster.sharding
 
 import java.net.URLEncoder
 import java.util.concurrent.ConcurrentHashMap
-
 import scala.collection.immutable
 import scala.concurrent.Await
 import scala.concurrent.Future
 import scala.concurrent.duration._
 import scala.util.Success
-
 import akka.actor.Actor
 import akka.actor.ActorLogging
 import akka.actor.ActorRef
@@ -47,6 +45,7 @@ import akka.persistence._
 import akka.pattern.ask
 import akka.pattern.pipe
 import akka.util.ByteString
+import akka.actor.Address
 
 /**
  * This extension provides sharding functionality of actors in a cluster.
@@ -612,6 +611,29 @@ object ShardRegion {
    */
   def gracefulShutdownInstance = GracefulShutdown
 
+  /*
+   * Send this message to the `ShardRegion` actor to request for [[CurrentRegions]],
+   * which contains the addresses of all registered regions.
+   * Intended for testing purpose to see when cluster sharding is "ready".
+   */
+  @SerialVersionUID(1L) final case object GetCurrentRegions extends ShardRegionCommand
+
+  def getCurrentRegionsInstance = GetCurrentRegions
+
+  /**
+   * Reply to [[GetCurrentRegions]]
+   */
+  @SerialVersionUID(1L) final case class CurrentRegions(regions: Set[Address]) {
+    /**
+     * Java API
+     */
+    def getRegions: java.util.Set[Address] = {
+      import scala.collection.JavaConverters._
+      regions.asJava
+    }
+
+  }
+
   private case object Retry extends ShardRegionCommand
 
   private def roleOption(role: String): Option[String] =
@@ -828,6 +850,12 @@ class ShardRegion(
       gracefulShutdownInProgress = true
       sendGracefulShutdownToCoordinator()
 
+    case GetCurrentRegions ⇒
+      coordinator match {
+        case Some(c) ⇒ c.forward(GetCurrentRegions)
+        case None    ⇒ sender() ! CurrentRegions(Set.empty)
+      }
+
     case _ ⇒ unhandled(cmd)
   }
 
@@ -1846,6 +1874,13 @@ class ShardCoordinator(settings: ClusterShardingSettings, allocationStrategy: Sh
       // it will soon be stopped when singleton is stopped
       context.become(shuttingDown)
 
+    case ShardRegion.GetCurrentRegions ⇒
+      val reply = ShardRegion.CurrentRegions(persistentState.regions.keySet.map { ref ⇒
+        if (ref.path.address.host.isEmpty) Cluster(context.system).selfAddress
+        else ref.path.address
+      })
+      sender() ! reply
+
     case _: CurrentClusterState ⇒
   }
 
diff --git a/akka-cluster-sharding/src/multi-jvm/scala/akka/cluster/sharding/ClusterShardingSpec.scala b/akka-cluster-sharding/src/multi-jvm/scala/akka/cluster/sharding/ClusterShardingSpec.scala
index 97814ca3d0..a4184fa566 100644
--- a/akka-cluster-sharding/src/multi-jvm/scala/akka/cluster/sharding/ClusterShardingSpec.scala
+++ b/akka-cluster-sharding/src/multi-jvm/scala/akka/cluster/sharding/ClusterShardingSpec.scala
@@ -5,6 +5,8 @@ package akka.cluster.sharding
 
 import akka.cluster.sharding.ShardCoordinator.Internal.{ ShardStopped, HandOff }
 import akka.cluster.sharding.ShardRegion.Passivate
+import akka.cluster.sharding.ShardRegion.GetCurrentRegions
+import akka.cluster.sharding.ShardRegion.CurrentRegions
 import language.postfixOps
 import scala.concurrent.duration._
 import com.typesafe.config.ConfigFactory
@@ -264,6 +266,9 @@ class ClusterShardingSpec extends MultiNodeSpec(ClusterShardingSpec) with STMult
         region ! EntryEnvelope(1, Decrement)
         region ! Get(1)
         expectMsg(2)
+
+        region ! GetCurrentRegions
+        expectMsg(CurrentRegions(Set(Cluster(system).selfAddress)))
       }
 
       enterBarrier("after-2")
@@ -308,6 +313,9 @@ class ClusterShardingSpec extends MultiNodeSpec(ClusterShardingSpec) with STMult
         region ! Get(2)
         expectMsg(3)
         lastSender.path should ===(region.path / "2" / "2")
+
+        region ! GetCurrentRegions
+        expectMsg(CurrentRegions(Set(Cluster(system).selfAddress, node(first).address)))
       }
 
       enterBarrier("after-3")