Kim Richards wrote a touching tribute to her ex-husband Monty Brinson, who died of cancer on Sunday.

"Yesterday I said goodbye to [the] best the friend I've ever had in my life," Richards wrote on Instagram. "Monty was an amazing person with an amazing soul ... We shared over 30 years of Love & Happiness and brought a beautiful daughter into world. I am so grateful for all that we shared."

Brinson and Richards were married from 1985 to 1988. The couple, who share 29-year-old daughter Brooke, stayed close following the divorce, with the Real Housewives of Beverly Hills star taking care of Brinson in recent years as his lung cancer worsened.

Kim Richards' ex-husband Monty Brinson dies

"My angel in heaven," Richards' post continued, "and I know that we be together again one day. I will carry you in my heart always my love...until then, may you rest in peace."

Richards' often estranged sister Kyle honored Monty on her own Instagram, writing: "We love you @montybrinson you will be missed dearly. The kindest, gentlest soul who inspired so many with his positive attitude throughout his battle with cancer. May you rest in peace now.