Kris Humphries must "carefully watch his words" on his Good Morning America appearance tomorrow.

Kim Kardashian's estranged husband is scheduled to speak on the morning television programme on Friday.

According to the prenuptial agreement that he signed before marrying Kim in August, Kris is restricted from revealing certain details about their relationship.

"Kris has to carefully watch his words," a source told RadarOnline.

"It's certain Kris will express sadness about the marriage ending, but he can't get into detail about reasons he decided to seek the annulment on grounds of fraud."

Under the terms of the prenup, Kris is forbidden from discussing the provisions of his relationship with Kim or the current divorce proceedings from the reality star.

Kris filed for an annulment of the marriage last month where he has to prove that his union with Kim occurred as a result of fraud.

If Kris is awarded an annulment and the prenuptial agreement is dismissed, he will then be legally permitted to discuss his relationship with Kim uninhibitedly.

Kim, Kim's divorce attorney and the star's mother Kris Jenner are all expected to be watching the programme closely tomorrow morning to ensure that he does not violate the terms of the prenup.

Kim filed for divorce from professional basketball player Kris Humphries after 72 days of marriage on Halloween.