diff --git a/src/builtin-addons/core/template-completion-provider.ts b/src/builtin-addons/core/template-completion-provider.ts
index 9231078a..43110ade 100644
--- a/src/builtin-addons/core/template-completion-provider.ts
+++ b/src/builtin-addons/core/template-completion-provider.ts
@@ -31,6 +31,7 @@ import {
   isScopedAngleTagName,
   isSpecialHelperStringPositionalParam,
   isFirstParamOfOnModifier,
+  isAttributeValueConcatMustachePath,
 } from '../../utils/ast-helpers';
 import {
   listComponents,
@@ -576,6 +577,13 @@ export default class TemplateCompletionProvider {
         const yields = await this.getParentComponentYields(focusPath.parent);
 
         completions.push(...yields);
+      } else if (isAttributeValueConcatMustachePath(focusPath)) {
+        const ignoredHelpers = ['helper', 'modifier', 'component'];
+        const items = await this.getMustachePathCandidates(root);
+        const localCandidates = await this.getLocalPathExpressionCandidates(uri, originalText);
+
+        completions.push(...items.filter((el) => el.detail === 'helper' && !ignoredHelpers.includes(el.label)));
+        completions.push(...localCandidates);
       } else if (isAngleComponentPath(focusPath)) {
         logDebugInfo('isAngleComponentPath');
         // <Foo>
diff --git a/src/utils/ast-helpers.ts b/src/utils/ast-helpers.ts
index db70e267..e2d34e2c 100644
--- a/src/utils/ast-helpers.ts
+++ b/src/utils/ast-helpers.ts
@@ -398,6 +398,36 @@ export function isScopedAngleTagName(path: ASTPath): boolean {
   return !HTML_TAGS.includes(node.tag);
 }
 
+export function isAttributeValueConcatMustachePath(path: ASTPath): boolean {
+  const node = path.node as ASTv1.PathExpression;
+
+  if (!isPathExpression(node)) {
+    return false;
+  }
+
+  const parent = path.parent as ASTv1.MustacheStatement;
+
+  if (!hasNodeType(parent, 'MustacheStatement')) {
+    return false;
+  }
+
+  if (parent.path !== node) {
+    return false;
+  }
+
+  const parentPath = path.parentPath;
+
+  if (!parentPath) {
+    return false;
+  }
+
+  if (!hasNodeType(parentPath.parent, 'ConcatStatement')) {
+    return false;
+  }
+
+  return true;
+}
+
 export function isAngleComponentPath(path: ASTPath): boolean {
   const node = path.node as unknown as ASTv1.ElementNode;
 
diff --git a/test/__snapshots__/integration-test.ts.snap b/test/__snapshots__/integration-test.ts.snap
index feda89ed..4d1d8733 100644
--- a/test/__snapshots__/integration-test.ts.snap
+++ b/test/__snapshots__/integration-test.ts.snap
@@ -280,6 +280,75 @@ Object {
 }
 `;
 
+exports[`integration async fs enabled: false Able to provide autocomplete information for MustacheStatements inside ConcatStatements support helper names autocomplete inside class attribute values 1`] = `
+Object {
+  "addonsMeta": Array [],
+  "registry": Object {
+    "component": Object {
+      "hello": Array [
+        "app/components/hello/index.hbs",
+      ],
+    },
+    "helper": Object {
+      "bar": Array [
+        "app/helpers/bar.js",
+      ],
+      "baz": Array [
+        "app/helpers/baz.ts",
+      ],
+    },
+  },
+  "response": Array [
+    Object {
+      "data": Object {
+        "files": Array [
+          "app/helpers/bar.js",
+        ],
+      },
+      "detail": "helper",
+      "kind": 3,
+      "label": "bar",
+      "textEdit": Object {
+        "newText": "bar",
+        "range": Object {
+          "end": Object {
+            "character": 19,
+            "line": 0,
+          },
+          "start": Object {
+            "character": 18,
+            "line": 0,
+          },
+        },
+      },
+    },
+    Object {
+      "data": Object {
+        "files": Array [
+          "app/helpers/baz.ts",
+        ],
+      },
+      "detail": "helper",
+      "kind": 3,
+      "label": "baz",
+      "textEdit": Object {
+        "newText": "baz",
+        "range": Object {
+          "end": Object {
+            "character": 19,
+            "line": 0,
+          },
+          "start": Object {
+            "character": 18,
+            "line": 0,
+          },
+        },
+      },
+    },
+  ],
+}
+`;
+
 exports[`integration async fs enabled: false Able to provide autocomplete information for angle component arguments names support template-only collocated components arguments extraction 1`] = `
 Object {
   "addonsMeta": Array [],
@@ -4206,6 +4275,75 @@ Object {
 }
 `;
 
+exports[`integration async fs enabled: true Able to provide autocomplete information for MustacheStatements inside ConcatStatements support helper names autocomplete inside class attribute values 1`] = `
+Object {
+  "addonsMeta": Array [],
+  "registry": Object {
+    "component": Object {
+      "hello": Array [
+        "app/components/hello/index.hbs",
+      ],
+    },
+    "helper": Object {
+      "bar": Array [
+        "app/helpers/bar.js",
+      ],
+      "baz": Array [
+        "app/helpers/baz.ts",
+      ],
+    },
+  },
+  "response": Array [
+    Object {
+      "data": Object {
+        "files": Array [
+          "app/helpers/bar.js",
+        ],
+      },
+      "detail": "helper",
+      "kind": 3,
+      "label": "bar",
+      "textEdit": Object {
+        "newText": "bar",
+        "range": Object {
+          "end": Object {
+            "character": 19,
+            "line": 0,
+          },
+          "start": Object {
+            "character": 18,
+            "line": 0,
+          },
+        },
+      },
+    },
+    Object {
+      "data": Object {
+        "files": Array [
+          "app/helpers/baz.ts",
+        ],
+      },
+      "detail": "helper",
+      "kind": 3,
+      "label": "baz",
+      "textEdit": Object {
+        "newText": "baz",
+        "range": Object {
+          "end": Object {
+            "character": 19,
+            "line": 0,
+          },
+          "start": Object {
+            "character": 18,
+            "line": 0,
+          },
+        },
+      },
+    },
+  ],
+}
+`;
+
 exports[`integration async fs enabled: true Able to provide autocomplete information for angle component arguments names support template-only collocated components arguments extraction 1`] = `
 Object {
   "addonsMeta": Array [],
diff --git a/test/integration-test.ts b/test/integration-test.ts
index 321778d6..e0ec3f8e 100644
--- a/test/integration-test.ts
+++ b/test/integration-test.ts
@@ -1629,6 +1629,32 @@ describe('integration', function () {
         });
       });
 
+      describe('Able to provide autocomplete information for MustacheStatements inside ConcatStatements', () => {
+        it('support helper names autocomplete inside class attribute values', async () => {
+          const result = await getResult(
+            CompletionRequest.method,
+            connection,
+            {
+              app: {
+                helpers: {
+                  'bar.js': '',
+                  'baz.ts': '',
+                },
+                components: {
+                  hello: {
+                    'index.hbs': '<div class="foo {{b">a</div>',
+                  },
+                },
+              },
+            },
+            'app/components/hello/index.hbs',
+            { line: 0, character: 19 }
+          );
+
+          expect(result).toMatchSnapshot();
+        });
+      });
+
       describe('Able to provide autocomplete information for local context access', () => {
         it('support collocated components', async () => {
           const result = await getResult(