diff --git a/api/peer_connection_proxy.h b/api/peer_connection_proxy.h
index 5c1d4b768a..43802f11e7 100644
--- a/api/peer_connection_proxy.h
+++ b/api/peer_connection_proxy.h
@@ -133,9 +133,11 @@ PROXY_METHOD1(bool, RemoveIceCandidates, const std::vector<cricket::Candidate>&)
 PROXY_METHOD1(RTCError, SetBitrate, const BitrateSettings&)
 PROXY_METHOD1(void, SetAudioPlayout, bool)
 PROXY_METHOD1(void, SetAudioRecording, bool)
-PROXY_METHOD1(rtc::scoped_refptr<DtlsTransportInterface>,
-              LookupDtlsTransportByMid,
-              const std::string&)
+// This method will be invoked on the network thread. See
+// PeerConnectionFactory::CreatePeerConnectionOrError for more details.
+PROXY_WORKER_METHOD1(rtc::scoped_refptr<DtlsTransportInterface>,
+                     LookupDtlsTransportByMid,
+                     const std::string&)
 // This method will be invoked on the network thread. See
 // PeerConnectionFactory::CreatePeerConnectionOrError for more details.
 PROXY_WORKER_CONSTMETHOD0(rtc::scoped_refptr<SctpTransportInterface>,
diff --git a/pc/peer_connection.cc b/pc/peer_connection.cc
index a340f9845d..1766bf5163 100644
--- a/pc/peer_connection.cc
+++ b/pc/peer_connection.cc
@@ -1629,8 +1629,7 @@ void PeerConnection::StopRtcEventLog() {
 
 rtc::scoped_refptr<DtlsTransportInterface>
 PeerConnection::LookupDtlsTransportByMid(const std::string& mid) {
-  RTC_DCHECK_RUN_ON(signaling_thread());
-  // TODO(tommi): Move to the network thread - this hides an invoke.
+  RTC_DCHECK_RUN_ON(network_thread());
   return transport_controller_->LookupDtlsTransportByMid(mid);
 }