Priscilla Presley and Riley Keough are no longer speaking amid the row over Lisa Marie Presley's trust.
The late singer died on 12 January aged 54 and two weeks later, her mother Priscilla filed a petition questioning the "authenticity and validity" of an amendment made to her daughter's trust - which includes her late father Elvis Presley's iconic home Graceland and 15 percent ownership of his estate -in 2016 which removed her and business manager Barry Siegel as trustees and appointed Lisa Marie's children, Riley and the late Benjamin Keough instead.
The 'Runaways' actress is said to be "heartbroken" over the rift between her and her grandmother, but the pair are only communicating through their respective legal teams.
A source told 'Entertainment Tonight': "It has been a very tense and heartbreaking few weeks for both Riley and Priscilla. Riley has been mourning the loss of her mother and is heartbroken to have to deal with a trust dispute with a family member.
"Priscilla is adamant that she has a valid case and that she will prevail in court. Riley and Priscilla aren't communicating at this time, but have been in communication through lawyers.
The 'Daisy Jones and the Six' actress - who has a baby daughter with husband Ben Smith-Petersen - is keen to settle the matter privately without a lengthy legal battle.
The insider added: "They are both gearing up for court, [but] Riley would prefer to settle this dispute privately.
"She is heartbroken that this has turned into a public matter and knows her mother would never want this. Riley is very stressed at the moment and has been trying to keep a positive attitude and outlook ahead of her new series coming out.
"Her daughter and husband have been keeping her in good spirits."
As for Priscilla, the insider said the 77-year-old star is doing what she feels "is right in her heart" and is determined to pursue the matter because she's still "convinced" the 2016 amendment was faked.
The source said: "She is convinced that old documents had been forged."
Lisa Marie's spokesperson previously confirmed Graceland would go to her daughters, Riley, 33, and 14-year-old twins Harper and Finley.
