diff --git a/pymule/__init__.py b/pymule/__init__.py
index 549b433d41d796401925fbe1ee3b0188051a8d96..f4f449d68700c7cfd0922e24872eb271a38a52ee 100644
--- a/pymule/__init__.py
+++ b/pymule/__init__.py
@@ -16,6 +16,6 @@ from loader import importreg, pattern, setup, sigma,                          \
                    mergeset, mergeseeds, mergefks,                            \
                    addsets, scaleset
 
-from plot import errorband, kplot
+from plot import errorband, kplot, watermark
 
 from constants import pi, alpha, GF, conv, Mmu, Mel, Mtau
diff --git a/pymule/plot.py b/pymule/plot.py
index 398ffe4142a6b0ac2daae0a5f5c31129fd495005..fae4ee848fb4e2b88667cb179b730fb55744c954 100644
--- a/pymule/plot.py
+++ b/pymule/plot.py
@@ -14,6 +14,20 @@ rc('text.latex', preamble="\n".join([
 ]))
 
 
+def watermark(fig, txt='PRELIMINARY', fontsize=60, rotation=20):
+    axs = fig.axes
+    corners = matplotlib.transforms.Bbox.union(
+        [i.get_position() for i in axs]
+    ).corners()
+    center = np.average(corners, axis=0)
+    fig.text(
+        center[0], center[1],
+        txt,
+        fontsize=fontsize, rotation=rotation,
+        ha='center', va='center', alpha=0.1
+    )
+
+
 def errorband(p, ax=None, col='default', underflow=False, overflow=False):
     if ax is None:
         ax = plt.gca()