diff --git a/selfdrive/modeld/models/commonmodel.pxd b/selfdrive/modeld/models/commonmodel.pxd
index 9f3f9bf27b..57b79aeafb 100644
--- a/selfdrive/modeld/models/commonmodel.pxd
+++ b/selfdrive/modeld/models/commonmodel.pxd
@@ -12,6 +12,8 @@ cdef extern from "common/clutil.h":
   cl_context cl_create_context(cl_device_id)
 
 cdef extern from "selfdrive/modeld/models/commonmodel.h":
+  float sigmoid(float)
+
   cppclass ModelFrame:
     int buf_size
     ModelFrame(cl_device_id, cl_context)
diff --git a/selfdrive/modeld/models/commonmodel_pyx.pyx b/selfdrive/modeld/models/commonmodel_pyx.pyx
index 88b0d16c99..e33d301aff 100644
--- a/selfdrive/modeld/models/commonmodel_pyx.pyx
+++ b/selfdrive/modeld/models/commonmodel_pyx.pyx
@@ -8,7 +8,10 @@ from libc.string cimport memcpy
 from cereal.visionipc.visionipc cimport cl_mem
 from cereal.visionipc.visionipc_pyx cimport VisionBuf, CLContext as BaseCLContext
 from .commonmodel cimport CL_DEVICE_TYPE_DEFAULT, cl_get_device_id, cl_create_context
-from .commonmodel cimport mat3, ModelFrame as cppModelFrame
+from .commonmodel cimport mat3, sigmoid as cppSigmoid, ModelFrame as cppModelFrame
+
+def sigmoid(x):
+  return cppSigmoid(x)
 
 cdef class CLContext(BaseCLContext):
   def __cinit__(self):