diff --git a/modules/rtp_rtcp/source/rtp_rtcp_impl2_unittest.cc b/modules/rtp_rtcp/source/rtp_rtcp_impl2_unittest.cc
index 123b68a10d..01085d1a33 100644
--- a/modules/rtp_rtcp/source/rtp_rtcp_impl2_unittest.cc
+++ b/modules/rtp_rtcp/source/rtp_rtcp_impl2_unittest.cc
@@ -47,11 +47,13 @@ namespace webrtc {
 namespace {
 constexpr uint32_t kSenderSsrc = 0x12345;
 constexpr uint32_t kReceiverSsrc = 0x23456;
+constexpr uint32_t kRtxSenderSsrc = 0x12346;
 constexpr TimeDelta kOneWayNetworkDelay = TimeDelta::Millis(100);
 constexpr uint8_t kBaseLayerTid = 0;
 constexpr uint8_t kHigherLayerTid = 1;
 constexpr uint16_t kSequenceNumber = 100;
 constexpr uint8_t kPayloadType = 100;
+constexpr uint8_t kRtxPayloadType = 98;
 constexpr int kWidth = 320;
 constexpr int kHeight = 100;
 constexpr int kCaptureTimeMsToRtpTimestamp = 90;  // 90 kHz clock.
@@ -264,7 +266,6 @@ class RtpRtcpModule : public RtcpPacketTypeCounterObserver,
     CreateModuleImpl();
   }
 
- private:
   void CreateModuleImpl() {
     RtpRtcpInterface::Configuration config;
     config.audio = false;
@@ -275,6 +276,8 @@ class RtpRtcpModule : public RtcpPacketTypeCounterObserver,
     config.rtt_stats = &rtt_stats_;
     config.rtcp_report_interval_ms = rtcp_report_interval_.ms();
     config.local_media_ssrc = is_sender_ ? kSenderSsrc : kReceiverSsrc;
+    config.rtx_send_ssrc =
+        is_sender_ ? absl::make_optional(kRtxSenderSsrc) : absl::nullopt;
     config.need_rtp_packet_infos = true;
     config.non_sender_rtt_measurement = true;
     config.field_trials = &trials_;
@@ -285,6 +288,7 @@ class RtpRtcpModule : public RtcpPacketTypeCounterObserver,
     impl_->SetRTCPStatus(RtcpMode::kCompound);
   }
 
+ private:
   std::map<uint32_t, RtcpPacketTypeCounter> counter_map_;
   absl::optional<SentPacket> last_sent_packet_;
   VideoFecGenerator* fec_generator_ = nullptr;
@@ -1075,6 +1079,99 @@ TEST_P(RtpRtcpImpl2Test, GeneratesUlpfec) {
   EXPECT_EQ(fec_packet.payload()[0], kUlpfecPayloadType);
 }
 
+TEST_P(RtpRtcpImpl2Test, RtpStateReflectsCurrentState) {
+  // Verify that that each of the field of GetRtpState actually reflects
+  // the current state.
+
+  // Current time will be used for `timestamp`, `capture_time_ms` and
+  // `last_timestamp_time_ms`.
+  const int64_t time_ms = time_controller_.GetClock()->TimeInMilliseconds();
+
+  // Use different than default sequence number to test `sequence_number`.
+  const uint16_t kSeq = kSequenceNumber + 123;
+  // Hard-coded value for `start_timestamp`.
+  const uint32_t kStartTimestamp = 3456;
+  const int64_t capture_time_ms = time_ms;
+  const uint32_t timestamp = capture_time_ms * kCaptureTimeMsToRtpTimestamp;
+
+  sender_.impl_->SetSequenceNumber(kSeq - 1);
+  sender_.impl_->SetStartTimestamp(kStartTimestamp);
+  EXPECT_TRUE(SendFrame(&sender_, sender_video_.get(), kBaseLayerTid));
+
+  // Simulate an RTCP receiver report in order to populate `ssrc_has_acked`.
+  RTCPReportBlock ack;
+  ack.source_ssrc = kSenderSsrc;
+  ack.extended_highest_sequence_number = kSeq;
+  sender_.impl_->OnReceivedRtcpReportBlocks({ack});
+
+  RtpState state = sender_.impl_->GetRtpState();
+  EXPECT_EQ(state.sequence_number, kSeq);
+  EXPECT_EQ(state.start_timestamp, kStartTimestamp);
+  EXPECT_EQ(state.timestamp, timestamp);
+  EXPECT_EQ(state.capture_time_ms, capture_time_ms);
+  EXPECT_EQ(state.last_timestamp_time_ms, time_ms);
+  EXPECT_EQ(state.ssrc_has_acked, true);
+
+  // Reset sender, advance time, restore state. Directly observing state
+  // is not feasible, so just verify returned state matches what we set.
+  sender_.CreateModuleImpl();
+  time_controller_.AdvanceTime(TimeDelta::Millis(10));
+  sender_.impl_->SetRtpState(state);
+
+  state = sender_.impl_->GetRtpState();
+  EXPECT_EQ(state.sequence_number, kSeq);
+  EXPECT_EQ(state.start_timestamp, kStartTimestamp);
+  EXPECT_EQ(state.timestamp, timestamp);
+  EXPECT_EQ(state.capture_time_ms, capture_time_ms);
+  EXPECT_EQ(state.last_timestamp_time_ms, time_ms);
+  EXPECT_EQ(state.ssrc_has_acked, true);
+}
+
+TEST_P(RtpRtcpImpl2Test, RtxRtpStateReflectsCurrentState) {
+  // Enable RTX.
+  sender_.impl_->SetStorePacketsStatus(/*enable=*/true, /*number_to_store=*/10);
+  sender_.impl_->SetRtxSendPayloadType(kRtxPayloadType, kPayloadType);
+  sender_.impl_->SetRtxSendStatus(kRtxRetransmitted | kRtxRedundantPayloads);
+
+  // `start_timestamp` is the only timestamp populate in the RTX state.
+  const uint32_t kStartTimestamp = 3456;
+  sender_.impl_->SetStartTimestamp(kStartTimestamp);
+
+  // Send a frame and ask for a retransmit of the last packet. Capture the RTX
+  // packet in order to verify RTX sequence number.
+  EXPECT_TRUE(SendFrame(&sender_, sender_video_.get(), kBaseLayerTid));
+  time_controller_.AdvanceTime(TimeDelta::Millis(5));
+  sender_.impl_->OnReceivedNack(
+      std::vector<uint16_t>{sender_.transport_.last_packet_.SequenceNumber()});
+  RtpPacketReceived& rtx_packet = sender_.transport_.last_packet_;
+  EXPECT_EQ(rtx_packet.Ssrc(), kRtxSenderSsrc);
+
+  // Simulate an RTCP receiver report in order to populate `ssrc_has_acked`.
+  RTCPReportBlock ack;
+  ack.source_ssrc = kRtxSenderSsrc;
+  ack.extended_highest_sequence_number = rtx_packet.SequenceNumber();
+  sender_.impl_->OnReceivedRtcpReportBlocks({ack});
+
+  RtpState rtp_state = sender_.impl_->GetRtpState();
+  RtpState rtx_state = sender_.impl_->GetRtxState();
+  EXPECT_EQ(rtx_state.start_timestamp, kStartTimestamp);
+  EXPECT_EQ(rtx_state.ssrc_has_acked, true);
+  EXPECT_EQ(rtx_state.sequence_number, rtx_packet.SequenceNumber() + 1);
+
+  // Reset sender, advance time, restore state. Directly observing state
+  // is not feasible, so just verify returned state matches what we set.
+  // Needs SetRtpState() too in order to propagate start timestamp.
+  sender_.CreateModuleImpl();
+  time_controller_.AdvanceTime(TimeDelta::Millis(10));
+  sender_.impl_->SetRtpState(rtp_state);
+  sender_.impl_->SetRtxState(rtx_state);
+
+  rtx_state = sender_.impl_->GetRtxState();
+  EXPECT_EQ(rtx_state.start_timestamp, kStartTimestamp);
+  EXPECT_EQ(rtx_state.ssrc_has_acked, true);
+  EXPECT_EQ(rtx_state.sequence_number, rtx_packet.SequenceNumber() + 1);
+}
+
 INSTANTIATE_TEST_SUITE_P(WithAndWithoutOverhead,
                          RtpRtcpImpl2Test,
                          ::testing::Values(TestConfig{false},