David Schwimmer refused to appear on 'Keeping Up With The Kardashians'.

David Schwimmer

David Schwimmer

The former 'Friends' star plays Robert Kardashian in FX's 'American Crime Story' which tells the real life story of how the late lawyer's client O.J. Simpson was acquitted of murder and while David got some insight into his character from Robert's ex-wife Kris Jenner, he turned down the chance to speak to Robert's daughters because he didn't want to appear on their reality TV show.

He told The Hollywood Reporter: "The producers of ['Keeping Up With the Kardashians'] asked me if I wanted to talk to the daughters but I didn't feel that was necessary. And they wanted to do it on camera."

However, he found a two-hour phone conversation with Kris extremely helpful as he discovered "how much a man of faith Robert was, how he prayed at every meal and before every big business meeting and how he was this very compassionate, generous guy."

Robert, who died in 2003, defended O.J. at his trial where he was accused of the murder of his ex-wife, Nicole Brown Simpson, and her friend, Ronald Goldman.

The case is covered in the new series, 'American Crime Story: The People v. O.J. Simpson', which also stars Selma Blair and Cuba Gooding Jr.