There’s a BATTLE going on over Alan Thicke’s estate!
Thicke died of a heart attack in December, and now his oldest children -- singer Robin Thicke and his brother Brennan -- are going to court against his third wife!
Her name is Tanya Callau, and she was with Alan for 18 YEARS (married for 12).
The sons say Callau is claiming that her prenup is invalid, and is threatening to go to the tabloids unless they give her a bigger share of Alan's fortune. One of the main issues is Alan’s $3.5-million-dollar ranch in California. It was left to the KIDS, but it’s where Tanya lives.