diff --git a/src/index.d.ts b/src/index.d.ts
index 55e0a30..42b58a5 100644
--- a/src/index.d.ts
+++ b/src/index.d.ts
@@ -180,7 +180,10 @@ export type TVReturnProps<
   B extends ClassValue,
   EV extends TVVariants<ES>,
   ES extends TVSlots,
+  // @ts-expect-error
+  E extends TVReturnType = undefined,
 > = {
+  extend: E;
   base: B;
   slots: S;
   variants: V;
@@ -197,13 +200,15 @@ export type TVReturnType<
   C extends TVConfig<V, EV>,
   EV extends TVVariants<ES>,
   ES extends TVSlots,
+  // @ts-expect-error
+  E extends TVReturnType = undefined,
 > = {
   (props?: TVProps<V, S, C, EV, ES>): ES extends undefined
     ? S extends undefined
       ? string
       : {[K in TVSlotsWithBase<S, B>]: (slotProps?: ClassProp) => string}
     : {[K in TVSlotsWithBase<ES & S, B>]: (slotProps?: ClassProp) => string};
-} & TVReturnProps<V, S, B, EV, ES>;
+} & TVReturnProps<V, S, B, EV, ES, E>;
 
 export type TV = {
   <
@@ -229,7 +234,7 @@ export type TV = {
   >(
     options: {
       /**
-       * Extend allows easily compose components.
+       * Extend allows for easy composition of components.
        * @see https://www.tailwind-variants.org/docs/composing-components
        */
       extend?: E;
@@ -238,22 +243,22 @@ export type TV = {
        */
       base?: B;
       /**
-       * Slots allows you to separate an component into multiple parts.
+       * Slots allow you to separate a component into multiple parts.
        * @see https://www.tailwind-variants.org/docs/slots
        */
       slots?: S;
       /**
-       * Variants allows you to create multiple versions of the same component.
+       * Variants allow you to create multiple versions of the same component.
        * @see https://www.tailwind-variants.org/docs/variants#adding-variants
        */
       variants?: V;
       /**
-       * Compound variants allow apply classes to multiple variants at once.
+       * Compound variants allow you to apply classes to multiple variants at once.
        * @see https://www.tailwind-variants.org/docs/variants#compound-variants
        */
       compoundVariants?: CV;
       /**
-       * Compound slots allow apply classes to multiple slots at once.
+       * Compound slots allow you to apply classes to multiple slots at once.
        */
       compoundSlots?: TVCompoundSlots<V, S, B>;
       /**
@@ -263,11 +268,11 @@ export type TV = {
       defaultVariants?: DV;
     },
     /**
-     * The config object to modify the default configuration.
+     * The config object allows you to modify the default configuration.
      * @see https://www.tailwind-variants.org/docs/api-reference#config-optional
      */
     config?: C,
-  ): TVReturnType<V, S, B, C, EV, ES>;
+  ): TVReturnType<V, S, B, C, EV, ES, E>;
 };
 
 // main function
diff --git a/src/index.js b/src/index.js
index 859745b..2bd6455 100644
--- a/src/index.js
+++ b/src/index.js
@@ -55,6 +55,7 @@ const joinObjects = (obj1, obj2) => {
 
 export const tv = (options, configProp) => {
   const {
+    extend = null,
     slots: slotProps = {},
     variants: variantsProps = {},
     compoundVariants = [],
@@ -64,9 +65,15 @@ export const tv = (options, configProp) => {
 
   const config = {...defaultConfig, ...configProp};
 
-  const base = cnBase(options?.extend?.base, options?.base);
-  const variants = mergeObjects(variantsProps, options?.extend?.variants);
-  const defaultVariants = {...options?.extend?.defaultVariants, ...defaultVariantsProps};
+  const base = extend?.base ? cnBase(extend.base, options?.base) : options?.base;
+  const variants =
+    extend?.variants && !isEmptyObject(extend.variants)
+      ? mergeObjects(variantsProps, extend.variants)
+      : variantsProps;
+  const defaultVariants =
+    extend?.defaultVariants && !isEmptyObject(extend.defaultVariants)
+      ? {...extend.defaultVariants, ...defaultVariantsProps}
+      : defaultVariantsProps;
 
   // save twMergeConfig to the cache
   if (!isEmptyObject(config.twMergeConfig) && !isEqual(config.twMergeConfig, cachedTwMergeConfig)) {
@@ -83,19 +90,15 @@ export const tv = (options, configProp) => {
     : {};
 
   // merge slots with the "extended" slots
-  const slots = isEmptyObject(options?.extend?.slots)
+  const slots = isEmptyObject(extend?.slots)
     ? componentSlots
     : joinObjects(
-        options?.extend?.slots,
+        extend?.slots,
         isEmptyObject(componentSlots) ? {base: options?.base} : componentSlots,
       );
 
   const component = (props) => {
-    if (
-      isEmptyObject(variants) &&
-      isEmptyObject(slotProps) &&
-      isEmptyObject(options?.extend?.slots)
-    ) {
+    if (isEmptyObject(variants) && isEmptyObject(slotProps) && isEmptyObject(extend?.slots)) {
       return cn(base, props?.class, props?.className)(config);
     }
 
@@ -259,7 +262,7 @@ export const tv = (options, configProp) => {
 
     const getCompoundVariantClassNames = () => {
       const cvValues = getCompoundVariantsValue(compoundVariants);
-      const ecvValues = getCompoundVariantsValue(options?.extend?.compoundVariants);
+      const ecvValues = getCompoundVariantsValue(extend?.compoundVariants);
 
       return flatMergeArrays(ecvValues, cvValues);
     };
@@ -323,7 +326,7 @@ export const tv = (options, configProp) => {
     };
 
     // with slots
-    if (!isEmptyObject(slotProps) || !isEmptyObject(options?.extend?.slots)) {
+    if (!isEmptyObject(slotProps) || !isEmptyObject(extend?.slots)) {
       const compoundClassNames = getCompoundVariantClassNamesBySlot() ?? [];
       const compoundSlotClassNames = getCompoundSlotClassNameBySlot() ?? [];
 
@@ -366,6 +369,7 @@ export const tv = (options, configProp) => {
   };
 
   component.variantKeys = getVariantKeys();
+  component.extend = extend;
   component.base = base;
   component.slots = slots;
   component.variants = variants;
diff --git a/src/utils.js b/src/utils.js
index af3545f..0356394 100644
--- a/src/utils.js
+++ b/src/utils.js
@@ -7,18 +7,18 @@ export const isEmptyObject = (obj) =>
 export const isEqual = (obj1, obj2) => JSON.stringify(obj1) === JSON.stringify(obj2);
 
 function flat(arr, target) {
-    arr.forEach(function (el) {
-          if (Array.isArray(el)) flat(el, target);
-          else target.push(el);
-        });
+  arr.forEach(function (el) {
+    if (Array.isArray(el)) flat(el, target);
+    else target.push(el);
+  });
 }
 
 export function flatArray(arr) {
-    const flattened = [];
+  const flattened = [];
 
-    flat(arr, flattened);
+  flat(arr, flattened);
 
-    return flattened;
+  return flattened;
 }
 
 export const flatMergeArrays = (...arrays) => flatArray(arrays).filter(Boolean);