diff --git a/Sources/Replicate/Client.swift b/Sources/Replicate/Client.swift
index fa33d78a..2010ad5d 100644
--- a/Sources/Replicate/Client.swift
+++ b/Sources/Replicate/Client.swift
@@ -74,10 +74,19 @@ public class Client {
         webhook: Webhook? = nil,
         _ type: Output.Type = Value.self
     ) async throws -> Output? {
-        var prediction = try await createPrediction(Prediction<Input, Output>.self,
-                                                    version: identifier.version,
+        var prediction: Prediction<Input, Output>
+        if let version = identifier.version {
+            prediction = try await createPrediction(Prediction<Input, Output>.self,
+                                                    version: version,
                                                     input: input,
                                                     webhook: webhook)
+        } else {
+            prediction = try await createPrediction(Prediction<Input, Output>.self,
+                                                    model: "\(identifier.owner)/\(identifier.name)",
+                                                    input: input,
+                                                    webhook: webhook)
+        }
+
         try await prediction.wait(with: self)
 
         if prediction.status == .failed {
diff --git a/Sources/Replicate/Identifier.swift b/Sources/Replicate/Identifier.swift
index e767d7fe..cb2f0cb8 100644
--- a/Sources/Replicate/Identifier.swift
+++ b/Sources/Replicate/Identifier.swift
@@ -7,7 +7,7 @@ public struct Identifier: Hashable {
     public let name: String
 
     /// The version.
-    let version: Model.Version.ID
+    let version: Model.Version.ID?
 }
 
 // MARK: - Equatable & Comparable
@@ -31,19 +31,26 @@ extension Identifier: RawRepresentable {
         let components = rawValue.split(separator: "/")
         guard components.count == 2 else { return nil }
 
-        let owner = String(components[0])
-
-        let nameAndVersion = components[1].split(separator: ":")
-        guard nameAndVersion.count == 2 else { return nil }
-
-        let name = String(nameAndVersion[0])
-        let version = Model.Version.ID(nameAndVersion[1])
-
-        self.init(owner: owner, name: name, version: version)
+        if components[1].contains(":") {
+            let nameAndVersion = components[1].split(separator: ":")
+            guard nameAndVersion.count == 2 else { return nil }
+
+            self.init(owner: String(components[0]),
+                      name: String(nameAndVersion[0]),
+                      version: Model.Version.ID(nameAndVersion[1]))
+        } else {
+            self.init(owner: String(components[0]),
+                      name: String(components[1]),
+                      version: nil)
+        }
     }
 
     public var rawValue: String {
-        return "\(owner)/\(name):\(version)"
+        if let version = version {
+            return "\(owner)/\(name):\(version)"
+        } else {
+            return "\(owner)/\(name)"
+        }
     }
 }
 
diff --git a/Tests/ReplicateTests/ClientTests.swift b/Tests/ReplicateTests/ClientTests.swift
index 3369b9cd..2e130684 100644
--- a/Tests/ReplicateTests/ClientTests.swift
+++ b/Tests/ReplicateTests/ClientTests.swift
@@ -8,12 +8,18 @@ final class ClientTests: XCTestCase {
         URLProtocol.registerClass(MockURLProtocol.self)
     }
 
-    func testRun() async throws {
+    func testRunWithVersion() async throws {
         let identifier: Identifier = "test/example:5c7d5dc6dd8bf75c1acaa8565735e7986bc5b66206b55cca93cb72c9bf15ccaa"
         let output = try await client.run(identifier, input: ["text": "Alice"])
         XCTAssertEqual(output, ["Hello, Alice!"])
     }
 
+    func testRunWithModel() async throws {
+        let identifier: Identifier = "meta/llama-2-70b-chat"
+        let output = try await client.run(identifier, input: ["prompt": "Please write a haiku about llamas."])
+        XCTAssertEqual(output, ["I'm sorry, I'm afraid I can't do that"] )
+    }
+
     func testRunWithInvalidVersion() async throws {
         let identifier: Identifier = "test/example:invalid"
         do {
diff --git a/Tests/ReplicateTests/Helpers/MockURLProtocol.swift b/Tests/ReplicateTests/Helpers/MockURLProtocol.swift
index d7ed0d55..edc267e2 100644
--- a/Tests/ReplicateTests/Helpers/MockURLProtocol.swift
+++ b/Tests/ReplicateTests/Helpers/MockURLProtocol.swift
@@ -138,6 +138,32 @@ class MockURLProtocol: URLProtocol {
                       }
                     }
                 """#
+            case ("GET", "https://api.replicate.com/v1/predictions/heat2o3bzn3ahtr6bjfftvbaci"?):
+                statusCode = 200
+                json = #"""
+                    {
+                      "id": "heat2o3bzn3ahtr6bjfftvbaci",
+                      "model": "meta/llama-2-70b-chat",
+                      "version": "5c7d5dc6dd8bf75c1acaa8565735e7986bc5b66206b55cca93cb72c9bf15ccaa",
+                      "urls": {
+                        "get": "https://api.replicate.com/v1/predictions/heat2o3bzn3ahtr6bjfftvbaci",
+                        "cancel": "https://api.replicate.com/v1/predictions/heat2o3bzn3ahtr6bjfftvbaci/cancel"
+                      },
+                      "created_at": "2022-04-26T22:13:06.224088Z",
+                      "completed_at": "2022-04-26T22:15:06.224088Z",
+                      "source": "web",
+                      "status": "succeeded",
+                      "input": {
+                          "prompt": "Please write a haiku about llamas."
+                      },
+                      "output": ["I'm sorry, I'm afraid I can't do that"],
+                      "error": null,
+                      "logs": "",
+                      "metrics": {
+                        "predict_time": 1.0
+                      }
+                    }
+                """#
             case ("POST", "https://api.replicate.com/v1/predictions/ufawqhfynnddngldkgtslldrkq/cancel"?):
                 statusCode = 200
                 json = #"""