The White House said U.S. President Barack Obama will invite leaders of nearly 50 African governments to an August summit in Washington.
Lalley said AU chairman Nkosazana Dlamini-Zuma will also be invited to the meeting, which takes place on August 5 and 6.
The White House announced the summit on Tuesday, saying it would be used to strengthen U.S. trade and investment ties with the continent.
Officials said Obama also hopes to build on progress made since his June 2013 visit to Africa.
The White House said the countries that will receive invitations to the August summit include the Democratic Republic of Congo, Ethiopia, Kenya, Mali, Nigeria and South Sudan.