Amy Pinto Walsh is in court fighting for assets she says Kinkade wanted her to have. She was living with the famed "painter of light" when he overdosed on alcohol and valium in April.
ABC7 News media partner the San Jose Mercury News obtained a copy of a handwritten note which Pinto Walsh claims Kinkade wrote, giving her his Monte Sereno mansion and $10 million to establish a museum of his paintings there.
ABC7 News legal analyst Dean Johnson says it is a complex case.
"Are the things that are passed under the will, are they Thomas Kinkade's to give away? Remember California is a community property state," Johnson said.
Lawyers for Kinkade's estranged wife and his business holdings left court without comment Tuesday. Nanette Kinkade was married to the world famous artist for 30 years and the couple has four daughters.
Before any decision is made about the validity of the handwritten will, Tuesday's hearing will determine if the matter will be aired publicly or in secret binding arbitration.
"We really need to allow the judge to make his decision; that's the fair thing to do," Pinto Walsh's attorney Sonia Agee said.
Once the judge makes that decision, Pinto Walsh will not only have to prove the artist wrote the document will, but was also of sound mind when he did it.