Mill also argued that the judge had "disapproved" of Chan's secret relationship with the billionaire and this had affected his judgment.

Chan's legal team presented photo and video evidence to support its claim. It showed a short video clip of Wang posing on a Toyota SUV in shorts and a tank top, asking Chan what he would do if his darling fell off when the car started.

Mill argued the video - in which the two referred to each other as "silly pig" and "daddy" - along with several pictures, showed the two had a loving relationship akin to that of a husband and wife.

He said the original trial judge, Johnson Lam, had also failed to recognize the implications of about HK$3 billion Wang gave Chan over the years to bolster his financial standing as consummate to becoming her heir.

Mill also said it was improbable Chan would risk fraudulently laying claim to Wang's billions, given he was already flush with cash.

He added it was improbable a 2006 will produced by Chan was a forgery given the meticulousness that would have been needed to replicate three different handwriting styles, signatures and chops.

Shortly after the initial ruling, Hong Kong police arrested Chan on suspicion of forging the will, later releasing him on bail of HK$5 million.

The case gripped Hong Kong and generated blanket media coverage, with Chan often cast as a charlatan who duped the billionaire by promising to find her kidnapped husband and cure her cancer.

Wang's husband Teddy, who started the Chinachem Group property empire, was abducted in 1990 and declared legally dead in 1999. His body has never been found.

Chan's 10-day case continued at the High Court before appeal judges Doreen Le Pichon, Anthony Rogers and Susan Kwan on Tuesday.