diff --git a/core/connection.go b/core/connection.go
index ab4c0878..380c6652 100644
--- a/core/connection.go
+++ b/core/connection.go
@@ -193,7 +193,7 @@ func createConnectionStep(src, dst *ProvableChain) (*RelayMsgs, error) {
 		if len(srcUpdateHeaders) > 0 {
 			out.Dst = append(out.Dst, dst.Path().UpdateClients(srcUpdateHeaders, addr)...)
 		}
-		out.Dst = append(out.Dst, dst.Path().ConnAck(src.Path(), srcCsRes, srcConn, srcConsRes, addr))
+		out.Dst = append(out.Dst, dst.Path().ConnAck(src.Path(), srcCsRes, srcConn, srcConsRes, dstHostConsProof, addr))
 
 	// Handshake has started on dst end (2 steps done), relay `connOpenAck` and `updateClient` to src end
 	case srcConn.Connection.State == conntypes.INIT && dstConn.Connection.State == conntypes.TRYOPEN:
@@ -202,7 +202,7 @@ func createConnectionStep(src, dst *ProvableChain) (*RelayMsgs, error) {
 		if len(dstUpdateHeaders) > 0 {
 			out.Src = append(out.Src, src.Path().UpdateClients(dstUpdateHeaders, addr)...)
 		}
-		out.Src = append(out.Src, src.Path().ConnAck(dst.Path(), dstCsRes, dstConn, dstConsRes, addr))
+		out.Src = append(out.Src, src.Path().ConnAck(dst.Path(), dstCsRes, dstConn, dstConsRes, srcHostConsProof, addr))
 
 	// Handshake has confirmed on dst (3 steps done), relay `connOpenConfirm` and `updateClient` to src end
 	case srcConn.Connection.State == conntypes.TRYOPEN && dstConn.Connection.State == conntypes.OPEN:
diff --git a/core/pathEnd.go b/core/pathEnd.go
index f786bea2..c9e4f984 100644
--- a/core/pathEnd.go
+++ b/core/pathEnd.go
@@ -128,13 +128,14 @@ func (pe *PathEnd) ConnAck(
 	dstClientState *clienttypes.QueryClientStateResponse,
 	dstConnState *conntypes.QueryConnectionResponse,
 	dstConsState *clienttypes.QueryConsensusStateResponse,
+	hostConsensusStateProof []byte,
 	signer sdk.AccAddress,
 ) sdk.Msg {
 	cs, err := clienttypes.UnpackClientState(dstClientState.ClientState)
 	if err != nil {
 		panic(err)
 	}
-	return conntypes.NewMsgConnectionOpenAck(
+	msg := conntypes.NewMsgConnectionOpenAck(
 		pe.ConnectionID,
 		dst.ConnectionID,
 		cs,
@@ -146,6 +147,11 @@ func (pe *PathEnd) ConnAck(
 		conntypes.ExportedVersionsToProto(conntypes.GetCompatibleVersions())[0],
 		signer.String(),
 	)
+	msg.HostConsensusStateProof = hostConsensusStateProof
+	if err = msg.ValidateBasic(); err != nil {
+		panic(err)
+	}
+	return msg
 }
 
 // ConnConfirm creates a MsgConnectionOpenAck