Below is the list of tables from the database along with their columns and datatype. Need to generate an accurate SQL query for the question.
Only use the columns present in the respective table. Only use the columns which are required to generate the SQL query. Only use table joins if required and not otherwise.

### Tables ###
TABLE: CREATE TABLE table_29135051_3 ( broadcast_date VARCHAR, guest_s_ VARCHAR )

### Question ###
when was the episode on which barbara windsor and heston blumenthal guest starred broadcasted

### Accurate SQL ###

SELECT broadcast_date FROM table_29135051_3 WHERE guest_s_ = "Barbara Windsor and Heston Blumenthal"