Denise Richards knows she can "count on" Charlie Sheen when she needs him

Sharing photos of herself and Charlie at the premiere of the documentary this week, Denise wrote on Instagram: "We both looked at each other on the red carpet and just laughed. Charlie asked, "Is it 2002?" and I said, "It sure feels like it." Who would have thought?

"What a journey we've had- so many ups and downs. But when life gets tough, deep down we both know we can count on each other. I'm so proud of him, and truly honored he asked me to be part of his story. Congrats, Charles [heart emoji] (sic)"

The former Two and a Half Men actor - who has daughters Sami, 21, and 20-year-old Lola with Denise - made a cameo appearance on his ex-wife's reality show, Denise Richards and Her Wild Things, earlier this year.

In the scene, Lola went out for dinner with her parents and admitted she finds it hard to understand they were ever a couple.

She said: "You know what's so funny? I could never picture you guys being married. Like, sometimes I think about if you were still married and we all lived in the same house."

The 58-year-old actress replied: "We would have had fun."

Charlie agreed: "We would've."

Meanwhile, Sami previously revealed she has blocked her father's number and no longer speaks to him but Charlie recently insisted he has no idea why.

Speaking on Good Morning America, he said: "I feel like as long as everybody's still in the game, there's always a shot for a better tomorrow, you know. I don't really know what I did, that's the problem. I don't know what I'm supposed to yet apologise for. But I have absolute faith that it's not a forever thing, and her and I will work it out. You know, we have a history that's too valuable to let, you know, some moment destroy all of that."

And, Charlie revealed that since he got sober, his relationships with all of his other children, Lola, 16-year-old twins Max and Bob with Brooke Mueller and daughter Cassandra Estevez, 41, with a high school girlfriend, have improved.

He said: "We have relationships, you know? And we have legitimate ones. And they really have nothing to do with anything that I do for a living."