Anderson Cooper

Chokes Up

Over Brother's Suicide

9/19/2011 1:40 PM PDT BY TMZ STAFF

Anderson Cooper
is known for his fearlessness, especially when it comes to war zones. But it was a chat with his mom in a NYC studio that made him dissolve in tears.

In an interview for his new syndicated talk show, socialite and 80s jeans designer Gloria Vanderbilt told Anderson ... after his brother Carter leaped off a 14-story balcony more than two decades ago, she almost followed him.  What stopped her was Anderson.