Anne Meara passed away in May at the age of 85 and the 50-year-old "Zoolander 2" star admitted he finds it hard to believe she is dead, reported Parade magazine.
"Honestly, it happened so recently that I'm still processing it. It affects me constantly. You know, you're going through your life, everything is great and then like, Pow! She's not here. It's hard for me," Stiller said.
"To the end, my mother never lost her sense of humour. I feel a connection as deeply to my mom now as I did when she was here. I really felt with her that she wasn't just going away, because she believed, as I do, that after we die there is something more."
"Obviously, my dad is a huge person in my life. I love him. But my mom was the person that I most looked up to for her point of view, her humour.