diff --git a/internal/jujuapi/jimm.go b/internal/jujuapi/jimm.go
index 296f6c634..4fb3da8f5 100644
--- a/internal/jujuapi/jimm.go
+++ b/internal/jujuapi/jimm.go
@@ -4,6 +4,8 @@ package jujuapi
 
 import (
 	"context"
+	"fmt"
+	"net"
 	"strings"
 	"time"
 
@@ -169,6 +171,19 @@ func (r *controllerRoot) AddCloudToController(ctx context.Context, req apiparams
 func (r *controllerRoot) AddController(ctx context.Context, req apiparams.AddControllerRequest) (apiparams.ControllerInfo, error) {
 	const op = errors.Op("jujuapi.AddController")
 
+	if req.PublicAddress != "" {
+		host, port, err := net.SplitHostPort(req.PublicAddress)
+		if err != nil {
+			return apiparams.ControllerInfo{}, errors.E(op, err, errors.CodeBadRequest)
+		}
+		if host == "" {
+			return apiparams.ControllerInfo{}, errors.E(op, fmt.Sprintf("address %s: host not specified in public address", req.PublicAddress), errors.CodeBadRequest)
+		}
+		if port == "" {
+			return apiparams.ControllerInfo{}, errors.E(op, fmt.Sprintf("address %s: port not specified in public address", req.PublicAddress), errors.CodeBadRequest)
+		}
+	}
+
 	ctl := dbmodel.Controller{
 		Name:          req.Name,
 		PublicAddress: req.PublicAddress,
diff --git a/internal/jujuapi/jimm_test.go b/internal/jujuapi/jimm_test.go
index f24a8096b..9dc640898 100644
--- a/internal/jujuapi/jimm_test.go
+++ b/internal/jujuapi/jimm_test.go
@@ -153,6 +153,50 @@ func (s *jimmSuite) TestListControllersV3Unauthorized(c *gc.C) {
 	}})
 }
 
+func (s *jimmSuite) TestAddControllerPublicAddressWithoutPort(c *gc.C) {
+	conn := s.open(c, nil, "alice")
+	defer conn.Close()
+	client := api.NewClient(conn)
+
+	tests := []struct {
+		req           apiparams.AddControllerRequest
+		expectedError string
+	}{{
+		req: apiparams.AddControllerRequest{
+			Name:          "controller-2",
+			PublicAddress: "controller.test.com",
+			CACertificate: s.APIInfo(c).CACert,
+			Username:      s.APIInfo(c).Tag.Id(),
+			Password:      s.APIInfo(c).Password,
+		},
+		expectedError: `address controller.test.com: missing port in address \(bad request\)`,
+	}, {
+		req: apiparams.AddControllerRequest{
+			Name:          "controller-2",
+			PublicAddress: ":8080",
+			CACertificate: s.APIInfo(c).CACert,
+			Username:      s.APIInfo(c).Tag.Id(),
+			Password:      s.APIInfo(c).Password,
+		},
+		expectedError: `address :8080: host not specified in public address \(bad request\)`,
+	}, {
+		req: apiparams.AddControllerRequest{
+			Name:          "controller-2",
+			PublicAddress: "localhost:",
+			CACertificate: s.APIInfo(c).CACert,
+			Username:      s.APIInfo(c).Tag.Id(),
+			Password:      s.APIInfo(c).Password,
+		},
+		expectedError: `address localhost:: port not specified in public address \(bad request\)`,
+	}}
+
+	for _, test := range tests {
+		ci, err := client.AddController(&test.req)
+		c.Assert(err, gc.ErrorMatches, test.expectedError)
+		c.Check(ci, jc.DeepEquals, apiparams.ControllerInfo{})
+	}
+}
+
 func (s *jimmSuite) TestAddController(c *gc.C) {
 	conn := s.open(c, nil, "alice")
 	defer conn.Close()