Denise Richards shares heartfelt tribute to late ex Patrick Muldoon

Denise Richards has posted a "devastated" tribute to her late ex-boyfriend, Patrick Muldoon.

The pair, who dated for almost five years after co-starring in 1997's satirical space movie Starship Troopers, remained close friends until Patrick died, aged 57, following a heart attack on Sunday, 19 April.

Two days later, Denise, 55, took to social media to share her grief at losing her "best friend".

"This is so hard for me to put into words," Denise wrote in an Instagram post. "I am deeply heartbroken & devastated losing you. You were my best friend & my family."

She went on to explain how she and Patrick had met when she was still a teenager.

"We met in our first acting class, I was 19 never had an acting job and you were 21 a student at USC doing a recurring role on who's the boss," Denise wrote. "And here we are. 36 years later. My whole adult life & I don't know it without you."

Denise, who later married actor Charlie Sheen, with whom she had two daughters before divorcing four years later, added she "didn't know" how to live without Patrick's support.

She explained she had particularly relied on Patrick in the wake of the recent split from her second husband, Aaron Phypers.

"We've been each other's rock," she wrote. "Our memories together are endless. You've had my back and protected me more than anyone. I don't know what I'm going to do without you here. You're my voice of reason & pillar of strength. Especially during this last year of pain & heartache."