Top Chef host Padma Lakshmi is mourning the death of her longtime lover, Theodore Forstmann, who passed away from brain cancer on Sunday at the age of 71, RadarOnline.com has learned.

The billionaire businessman was the head of sports and modeling at talent agency IMG, he was recently ranked No. 242 among America's 400 Richest and is worth an estimated $1.8 billion, the International Business Journal reported.

Lakshmi and Forstmann have been dating for several years but kept their low-profile relationship private until the former model gave birth last year.