diff --git a/src/Api/Billing/Controllers/AccountsController.cs b/src/Api/Billing/Controllers/AccountsController.cs
index dec28f552e..1a10b2dcf7 100644
--- a/src/Api/Billing/Controllers/AccountsController.cs
+++ b/src/Api/Billing/Controllers/AccountsController.cs
@@ -3,10 +3,13 @@ using Bit.Api.Models.Request.Accounts;
 using Bit.Api.Models.Response;
 using Bit.Api.Utilities;
 using Bit.Core;
+using Bit.Core.Auth.UserFeatures.TwoFactorAuth.Interfaces;
 using Bit.Core.Billing.Models;
 using Bit.Core.Billing.Models.Business;
 using Bit.Core.Billing.Services;
 using Bit.Core.Exceptions;
+using Bit.Core.KeyManagement.Queries.Interfaces;
+using Bit.Core.Models.Business;
 using Bit.Core.Services;
 using Bit.Core.Settings;
 using Bit.Core.Utilities;
@@ -19,9 +22,59 @@ namespace Bit.Api.Billing.Controllers;
 [Authorize("Application")]
 public class AccountsController(
     IUserService userService,
+    ITwoFactorIsEnabledQuery twoFactorIsEnabledQuery,
+    IUserAccountKeysQuery userAccountKeysQuery,
     IFeatureService featureService,
     ILicensingService licensingService) : Controller
 {
+    // TODO: Remove when pm-24996-implement-upgrade-from-free-dialog and pm-24033-updat-premium-subscription-page are removed
+    [HttpPost("premium")]
+    public async Task<PaymentResponseModel> PostPremiumAsync(
+        PremiumRequestModel model,
+        [FromServices] GlobalSettings globalSettings)
+    {
+        var user = await userService.GetUserByPrincipalAsync(User);
+        if (user == null)
+        {
+            throw new UnauthorizedAccessException();
+        }
+
+        var valid = model.Validate(globalSettings);
+        UserLicense? license = null;
+        if (valid && globalSettings.SelfHosted)
+        {
+            license = await ApiHelpers.ReadJsonFileFromBody<UserLicense>(HttpContext, model.License);
+        }
+
+        if (!valid && !globalSettings.SelfHosted && string.IsNullOrWhiteSpace(model.Country))
+        {
+            throw new BadRequestException("Country is required.");
+        }
+
+        if (!valid || (globalSettings.SelfHosted && license == null))
+        {
+            throw new BadRequestException("Invalid license.");
+        }
+
+        var result = await userService.SignUpPremiumAsync(user, model.PaymentToken,
+            model.PaymentMethodType!.Value, model.AdditionalStorageGb.GetValueOrDefault(0), license,
+            new TaxInfo { BillingAddressCountry = model.Country, BillingAddressPostalCode = model.PostalCode });
+
+        var userTwoFactorEnabled = await twoFactorIsEnabledQuery.TwoFactorIsEnabledAsync(user);
+        var userHasPremiumFromOrganization = await userService.HasPremiumFromOrganization(user);
+        var organizationIdsClaimingActiveUser = await GetOrganizationIdsClaimingUserAsync(user.Id);
+        var accountKeys = await userAccountKeysQuery.Run(user);
+
+        var profile = new ProfileResponseModel(user, accountKeys, null, null, null, userTwoFactorEnabled,
+            userHasPremiumFromOrganization, organizationIdsClaimingActiveUser);
+        return new PaymentResponseModel
+        {
+            UserProfile = profile,
+            PaymentIntentClientSecret = result.Item2,
+            Success = result.Item1
+        };
+    }
+
     // TODO: Migrate to Query / AccountBillingVNextController as part of Premium -> Organization upgrade work.
     [HttpGet("subscription")]
     public async Task<SubscriptionResponseModel> GetSubscriptionAsync(