diff --git a/.github/workflows/test.yml b/.github/workflows/test.yml
index 3290a077..28f61de9 100644
--- a/.github/workflows/test.yml
+++ b/.github/workflows/test.yml
@@ -125,6 +125,45 @@ jobs:
           fi
         shell:
           bash
+      - name: Run changed-files with specific files from a source file
+        id: changed-files-specific-source-file
+        uses: ./
+        with:
+          files-from-source-file: |
+            test/changed-files-list.txt
+            test/changed-files-list.txt
+          files: |
+            .github/workflows/rebase.yml
+      - name: Verify any_changed files
+        if: "!contains(steps.changed-files-specific.outputs.all_modified_files, 'action.yml') && !contains(steps.changed-files-specific.outputs.all_modified_files, '.github/workflows/test.yml')"
+        run: |
+          if [[ "${{ steps.changed-files-specific.outputs.any_changed }}" != "false" ]]; then
+            echo "Invalid output: Expected (false) got (${{ steps.changed-files-specific.outputs.any_changed }})"
+            exit 1
+          fi
+        shell:
+          bash
+      - name: Show output
+        run: |
+          echo "${{ toJSON(steps.changed-files-specific.outputs) }}"
+        shell:
+          bash
+      - name: Run changed-files with specific files from a source file using a comma separator
+        id: changed-files-specific-comma-source-file
+        uses: ./
+        with:
+          files-from-source-file: |
+            test/changed-files-list.txt
+          separator: ","
+      - name: Verify any_changed files comma separator
+        if: "!contains(steps.changed-files-specific-comma.outputs.all_modified_files, 'action.yml') && !contains(steps.changed-files-specific-comma.outputs.all_modified_files, '.github/workflows/test.yml')"
+        run: |
+          if [[ "${{ steps.changed-files-specific.outputs.any_changed }}" != "false" ]]; then
+            echo "Invalid output: Expected (false) got (${{ steps.changed-files-specific.outputs.any_changed }})"
+            exit 1
+          fi
+        shell:
+          bash
       - name: Show output
         run: |
           echo "${{ toJSON(steps.changed-files-specific-comma.outputs) }}"
diff --git a/README.md b/README.md
index 4e700b18..3f03ee22 100644
--- a/README.md
+++ b/README.md
@@ -99,6 +99,7 @@ jobs:
 | separator     |  `string`   |    `true`     | `' '`                         |  Output string separator   |
 | files         |  `string` OR `string[]` |   `false`  |                      | Check for changes  <br> using only these list of file(s) <br> (Defaults to the entire repo) |
 | sha           |  `string`      |    `true`     | `${{ github.sha }}`           | Specify a different <br> commit SHA used for comparing changes  |
+| files-from-source-file |  `string`      |    `false`     |                    | Source file used populate <br>  the files input.  |
 
 ## Example
 
@@ -150,6 +151,22 @@ jobs:
         if: steps.changed-files-specific.outputs.any_changed == 'true'
         run: |
           echo "One or more files listed above has changed."
+      
+      - name: Use a source file or list of file(s) to populate to files input.
+        id: changed-files-specific-source-file
+        uses: ./
+        with:
+          files-from-source-file: |
+            test/changed-files-list.txt
+
+      - name: Use a source file or list of file(s) to populate to files input and optionally specify more files.
+        id: changed-files-specific-source-file-and-specify-files
+        uses: ./
+        with:
+          files-from-source-file: |
+            test/changed-files-list.txt
+          files: |
+            .github/workflows/rebase.yml
 
       - name: Use a different commit SHA
         id: changed-files-comma
diff --git a/action.yml b/action.yml
index 33d31016..f19591d6 100644
--- a/action.yml
+++ b/action.yml
@@ -10,6 +10,10 @@ inputs:
     description: 'Split character for array output'
     required: true
     default: " "
+  files-from-source-file:
+    description: 'Source file to populate the files input'
+    required: false
+    default: ""
   files:
     description: 'Check for changes using only this list of files (Defaults to the entire repo)'
     required: false
@@ -57,6 +61,22 @@ outputs:
 runs:
   using: 'composite'
   steps:
+    - run: |
+        FILES=()
+
+        if [[ -n $INPUT_FILES_FROM_SOURCE_FILE ]]; then
+          for file in $INPUT_FILES_FROM_SOURCE_FILE
+          do
+            FILES+=$(cat $file | sort -u | tr "\n" " " )
+          done
+        fi
+
+        echo "::set-output name=files::$FILES"
+      id: source-input-files
+      shell: bash
+      env:
+        INPUT_FILES: ${{ inputs.files }}
+        INPUT_FILES_FROM_SOURCE_FILE: ${{ inputs.files-from-source-file }}
     - run: |
         bash $GITHUB_ACTION_PATH/entrypoint.sh
       id: changed-files
@@ -68,7 +88,7 @@ runs:
         # https://github.community/t/input-variable-name-is-not-available-in-composite-run-steps/127611
         INPUT_SHA: ${{ inputs.sha }}
         INPUT_TOKEN: ${{ inputs.token }}
-        INPUT_FILES: ${{ inputs.files }}
+        INPUT_FILES: ${{ join(format('{0} {1}', inputs.files, steps.source-input-files.outputs.files), ' ') }}
         INPUT_SEPARATOR: ${{ inputs.separator }}
 
 branding:
diff --git a/entrypoint.sh b/entrypoint.sh
index 390eb7b3..57759ee8 100755
--- a/entrypoint.sh
+++ b/entrypoint.sh
@@ -43,7 +43,9 @@ fi
 
 echo "Retrieving changes between $PREV_SHA ($TARGET_BRANCH) → $CURR_SHA ($CURRENT_BRANCH)"
 
-if [[ -z "$INPUT_FILES" ]]; then
+UNIQUE_FILES=$(echo "$INPUT_FILES" | tr ' ' '\n' | sort -u | xargs)
+
+if [[ -z "$UNIQUE_FILES" ]]; then
   echo "Getting diff..."
   ADDED=$(git diff --diff-filter=A --name-only "$PREV_SHA" "$CURR_SHA" | tr "\n" "$INPUT_SEPARATOR" | sed -E "s/($INPUT_SEPARATOR)$//")
   COPIED=$(git diff --diff-filter=C --name-only "$PREV_SHA" "$CURR_SHA" | tr "\n" "$INPUT_SEPARATOR" | sed -E "s/($INPUT_SEPARATOR)$//")
@@ -66,7 +68,8 @@ else
   UNKNOWN_ARRAY=()
   ALL_CHANGED_ARRAY=()
   ALL_MODIFIED_FILES_ARRAY=()
-  for path in ${INPUT_FILES}
+
+  for path in ${UNIQUE_FILES}
   do
     echo "Checking for file changes: \"${path}\"..."
     IFS=" "
@@ -125,9 +128,9 @@ echo "Unknown files: $UNKNOWN"
 echo "All changed files: $ALL_CHANGED"
 echo "All modified files: $ALL_MODIFIED_FILES"
 
-if [[ -n "$INPUT_FILES" ]]; then
+if [[ -n "$UNIQUE_FILES" ]]; then
   # shellcheck disable=SC2001
-  ALL_INPUT_FILES=$(echo "$INPUT_FILES" | tr "\n" " " | xargs)
+  ALL_INPUT_FILES=$(echo "$UNIQUE_FILES" | tr "\n" " " | xargs)
 
   echo "Input files: ${ALL_INPUT_FILES[*]}"
   echo "Matching modified files: ${ALL_MODIFIED_FILES[*]}"
diff --git a/test/changed-files-list.txt b/test/changed-files-list.txt
new file mode 100644
index 00000000..3852a74e
--- /dev/null
+++ b/test/changed-files-list.txt
@@ -0,0 +1,4 @@
+.github/workflows/test.yml
+action.yml
+action.yml
+test/changed-files-list.txt
\ No newline at end of file