The singer attended Sean's charity bash in Beverly Hills on Saturday, where she made a speech detailing her love for her former spouse, before joking about his fondness for cigarettes.
She said: "It was great to finally meet her; you grow up hearing stories of your dad and Madonna and their tumultuous relationship and they were so young.
"It was cool to meet this woman who knew my dad at such a young age, it was great! They are close friends and so cool with each other. It's nice to see that respect still remains and there is still love for each other there. It makes me happy. It makes me think I can have that with my ex-boyfriends when we are older.
"It was kind of surreal to meet her. Like, my dad's ex-lover.
"I think he just really admires her work. They're just really good friends and I think it's sweet that they can have this relationship."