diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 04ececf..d9ae940 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -20,6 +20,12 @@ jobs:
           bump: major
           planned: 1000000000.0.0
         id: billionth
+      - name: Run local action with override=1.2.3
+        uses: ./
+        with:
+          bump: minor
+          override: 1.2.3
+        id: override
       - name: Run local action with build=foo
         uses: ./
         with:
@@ -56,9 +62,12 @@ jobs:
       - name: Ensure 1000000000.0.0 is greater than whatever the current version is
         run: |
           [[ "${{ steps.billionth.outputs.planned-is-valid }}" = "true" ]] || exit 1
-      - name: Check major bump
+      - name: Check major bump on billionth
         run: |
           [[ "${{ steps.billionth.outputs.bump }}" = "${{ steps.billionth.outputs.next-major }}" ]] || exit 1
+      - name: Check minor bump on override
+        run: |
+          [[ "${{ steps.override.outputs.bump }}" = "1.3.0" ]] || exit 1
       - name: Ensure next-build of foo-build is foo
         run: |
-          [[ "$(semver get build ${{ steps.foo-build.outputs.next-build }})" = "foo" ]] || exit 1
\ No newline at end of file
+          [[ "$(semver get build ${{ steps.foo-build.outputs.next-build }})" = "foo" ]] || exit 1
diff --git a/README.md b/README.md
index 03238e6..504c2b9 100644
--- a/README.md
+++ b/README.md
@@ -50,6 +50,7 @@ Note that the `tag` output is "as-is", including any prefix the semver might hav
 * `repo` If specified, this repository is checked out by the action. By default, no checkout occurs.
 * `path` Location to find the repository checkout. By default, this is `$github.workspace`.
 * `bump` If specified, the `bump` output will reflect the given version increment with respect to `current`.
+* `override` If specified, the `current` output will be set equal to `override`, and all other outputs are computed with respect to it (instead of using the greatest tag found in the repository). A given `override` must be a valid semantic version number.
 * `planned` If this is a valid semver greater than the `current` output, the `valid-planned` output is `true`.
 * `build` If specified, the `next-build` output will be generated featuring this string (and remain empty otherwise).
 * `prerelease` If specified, the `next-prerelease` output will be generated featuring this string (and remain empty otherwise).
diff --git a/action.yml b/action.yml
index a5ac06b..dd11e1f 100644
--- a/action.yml
+++ b/action.yml
@@ -14,6 +14,10 @@ inputs:
     type: string
     description: Requested version increment in bump output
     required: false
+  override:
+    type: string
+    description: Manually specified current version
+    required: false
   planned:
     type: string
     description: Version to compare against current
@@ -91,25 +95,34 @@ runs:
     - name: Find the greatest semver tag
       id: find
       working-directory: ${{ inputs.path }}
-      run: >
-        tag="$(greatest-semver-tag)";
-        if [[ tag = "0.0.0" ]]; then
-          echo "::set-output name=tag::$(greatest-semver-tag)"
-        else
-          echo "::set-output name=tag::$(greatest-semver-tag)"
-        fi
+      run: |
+        echo "::set-output name=tag::$(greatest-semver-tag)"
       shell: bash
     - name: Set current version based on stripped tag
       id: cur
-      run: |
-        echo "::set-output name=ver::$(echo "${{ steps.find.outputs.tag }}" | sed 's/^[^0-9]*//')"
+      run: >
+        if [[ "${{ inputs.override }}" != "" ]]; then
+          if [[ $(semver compare ${{ inputs.override }} 0.0.0) != "1" ]]; then
+            if [[ "${{ inputs.override }}" != "0.0.0" ]]; then
+              echo "Invalid override."; exit 1
+            fi
+          fi
+          echo "::set-output name=ver::${{ inputs.override }}"  
+        elif [[ "${{ steps.find.outputs.tag }}" = "" ]]; then
+          echo "::set-output name=ver::0.0.0"
+        else
+          echo "::set-output name=ver::$(echo "${{ steps.find.outputs.tag }}" | sed 's/^[^0-9]*//')"
+        fi
       shell: bash
     - name: Determine the prefix and set it
       id: prefix
       run: >
-        tag="${{ steps.find.outputs.tag }}";
         ver="${{ steps.cur.outputs.ver }}";
-        echo "::set-output name=str::$(echo ${tag%"$ver"})"
+        if [[ "${{ inputs.override }}" != "" ]]; then
+          echo "::set-output name=str::$(echo ${${{ inputs.override }}%"$ver"})"
+        elif [[ "${{ steps.find.outputs.tag }}" != "" ]]; then
+          echo "::set-output name=str::$(echo ${${{ steps.find.outputs.tag }}%"$ver"})"
+        fi
       shell: bash
     - name: Test if planned input is greater than current
       id: test
diff --git a/greatest-semver-tag.sh b/greatest-semver-tag.sh
index 7b4e2aa..50b8ee0 100755
--- a/greatest-semver-tag.sh
+++ b/greatest-semver-tag.sh
@@ -6,4 +6,8 @@ while IFS= read -r line; do
     fi
     #echo "... $line ..."
 done <<< "$(git tag)"
-echo $latest
+if [[ ${latest} != "0.0.0" ]]; then
+    echo ${latest}
+else
+   echo ""
+fi