Charlie Sheen's sobriety questioned by Richards

Denise Richards has said that she is not sure whether Charlie Sheen is sober.

During an appearance on Bravo's Watch What Happens on Thursday, Sheen's ex-wife said that she was "sad" to see the former Two and a Half Men star's current behaviour.

"For me, it's very sad to see him on this path," Richards said.

She added: "I've heard he's chosen to use me in part of his tour [material], and that's hurtful. But that's his choice… He can do what he wants in his show."

When asked about Sheen's sobriety, Richards responded: "I don't know if he's sober or not."

Sheen was booed heavily during his show in New York when he claimed to have recently embraced a sober lifestyle.

In March, Sheen accused Richards of stealing his pet dogs. The actor has promised to continue insulting his ex-wife until she returns his dogs.

Richards filed for divorce from Sheen in 2005, accusing him of alcohol and drug abuse. They have two daughters together, Sam and Lola.

Sheen recently lost a bid to gain full custody of his twin sons with Brooke Mueller.