diff --git a/mercurial/bundle2.py b/mercurial/bundle2.py
--- a/mercurial/bundle2.py
+++ b/mercurial/bundle2.py
@@ -1601,6 +1601,16 @@
         phasedata = phases.binaryencode(headsbyphase)
         bundler.newpart('phase-heads', data=phasedata)
 
+    if opts.get('streamv2', False):
+        # The generation of the stream part is currently in exchange but
+        # importing exchange create an import cycle. We could extract the
+        # generation of the stream part in bundle2 or another file.
+        from . import exchange
+        # The streamv2 part doesn't uses the source argument, we can refactor
+        # this once the bundle part generator has been extracted
+        source = None
+        exchange._getbundlestream2(bundler, repo, source, stream=True)
+
 def addparttagsfnodescache(repo, bundler, outgoing):
     # we include the tags fnode cache for the bundle changeset
     # (as an optional parts)