diff --git a/beacon-chain/rpc/prysm/v1alpha1/validator/proposer.go b/beacon-chain/rpc/prysm/v1alpha1/validator/proposer.go
index bcac5fd577..aee68deb54 100644
--- a/beacon-chain/rpc/prysm/v1alpha1/validator/proposer.go
+++ b/beacon-chain/rpc/prysm/v1alpha1/validator/proposer.go
@@ -189,6 +189,15 @@ func (vs *Server) computeStateRoot(ctx context.Context, block interfaces.SignedB
 }
 
 // SubmitValidatorRegistration submits validator registrations.
-func (vs *Server) SubmitValidatorRegistration(context.Context, *ethpb.SignedValidatorRegistrationsV1) (*emptypb.Empty, error) {
+func (vs *Server) SubmitValidatorRegistration(ctx context.Context, reg *ethpb.SignedValidatorRegistrationsV1) (*emptypb.Empty, error) {
+	// No-op is the builder is nil / not configured. The node should still function without a builder.
+	if vs.BlockBuilder == nil || !vs.BlockBuilder.Configured() {
+		return &emptypb.Empty{}, nil
+	}
+
+	if err := vs.BlockBuilder.RegisterValidator(ctx, reg.Messages); err != nil {
+		return nil, status.Errorf(codes.InvalidArgument, "Could not register block builder: %v", err)
+	}
+
 	return &emptypb.Empty{}, nil
 }
diff --git a/beacon-chain/rpc/prysm/v1alpha1/validator/proposer_test.go b/beacon-chain/rpc/prysm/v1alpha1/validator/proposer_test.go
index f68a3450cd..4821095e62 100644
--- a/beacon-chain/rpc/prysm/v1alpha1/validator/proposer_test.go
+++ b/beacon-chain/rpc/prysm/v1alpha1/validator/proposer_test.go
@@ -7,8 +7,10 @@ import (
 	"time"
 
 	"github.com/ethereum/go-ethereum/common"
+	"github.com/pkg/errors"
 	"github.com/prysmaticlabs/go-bitfield"
 	mock "github.com/prysmaticlabs/prysm/beacon-chain/blockchain/testing"
+	builderTest "github.com/prysmaticlabs/prysm/beacon-chain/builder/testing"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache"
 	"github.com/prysmaticlabs/prysm/beacon-chain/cache/depositcache"
 	b "github.com/prysmaticlabs/prysm/beacon-chain/core/blocks"
@@ -2504,6 +2506,23 @@ func TestProposer_PrepareBeaconProposer(t *testing.T) {
 	}
 }
 
+func TestProposer_SubmitValidatorRegistration(t *testing.T) {
+	ctx := context.Background()
+	proposerServer := &Server{}
+	reg := &ethpb.SignedValidatorRegistrationsV1{}
+	_, err := proposerServer.SubmitValidatorRegistration(ctx, reg)
+	require.NoError(t, err)
+	proposerServer = &Server{BlockBuilder: &builderTest.MockBuilderService{}}
+	_, err = proposerServer.SubmitValidatorRegistration(ctx, reg)
+	require.NoError(t, err)
+	proposerServer = &Server{BlockBuilder: &builderTest.MockBuilderService{HasConfigured: true}}
+	_, err = proposerServer.SubmitValidatorRegistration(ctx, reg)
+	require.NoError(t, err)
+	proposerServer = &Server{BlockBuilder: &builderTest.MockBuilderService{HasConfigured: true, ErrRegisterValidator: errors.New("bad")}}
+	_, err = proposerServer.SubmitValidatorRegistration(ctx, reg)
+	require.ErrorContains(t, "bad", err)
+}
+
 func majorityVoteBoundaryTime(slot types.Slot) (uint64, uint64) {
 	s := params.BeaconConfig().SlotsPerEpoch.Mul(uint64(params.BeaconConfig().EpochsPerEth1VotingPeriod))
 	slotStartTime := uint64(mockPOW.GenesisTime) + uint64((slot - (slot % (s))).Mul(params.BeaconConfig().SecondsPerSlot))