The pair left answerphone messages for 78-year-old Andrew, who played waiter Manuel in the classic comedy, in which they told him Russell had slept with his granddaughter and joked that the actor might kill himself as a result.
“We have received a letter of a complaint from Mr Sachs’s agent and would like to sincerely apologise to Mr Sachs for the offence caused,” a BBC spokeswoman said.
“We recognise that some of the content broadcast was unacceptable and offensive. We are reviewing how this came about and are responding to Mr Sachs personally.
“We also apologise to listeners for any offence caused.”
The pre-recorded calls were aired on Russell’s Radio 2 show. The pair began making calls after Sachs apparently did not answer his phone for a pre-arranged interview to promote a television show.
Jonathan, 47, left a message telling Sachs: “He f***** your granddaughter.”
Russell, 33, denied this, but after discussing how Sachs might hang himself as a result, the pair made a string of calls in which they ostensibly attempted to apologise for what was ‘just a joke’, but continued to leave lewd messages.
At one point, Russell sang: “I said some things I didn’t of oughta, like I had sex with your granddaughter, though it was consensual.”
A spokeswoman for Sachs said the actor was ‘upset’ by the incident but did not wish to comment further.