Denise Richards shares tribute to late ex Patrick Muldoon as she marks his 58th birthday: 'Wish I held you longer'

Denise Richards paid tribute to her late ex-boyfriend Patrick Muldoon in an Instagram post on Sunday, marking what would have been his 58th birthday following his passing this past April.

The 55-year-old actress posted a trio of images of the late actor, including a shot of the pair on a runway standing next to an aircraft.

'This was our last hug saying goodbye..... if only I hugged you tighter and longer,' said The Real Housewives of Beverly Hills alum. 'We had just gotten off our flight from Scotland.. a whirlwind weekend with our starship troopers family.'

The Downers Grove, Illinois native said Muldoon had been 'excited... to land at LAX' and be driven 'across the tarmac' by a private service.

Muldoon passed away at his home in Beverly Hills, California this past April 19 as a result of a heart attack.

The Daily Mail has reached out to representatives for Richards for further comment on the story.

Richards, who has been seen in films such as The World Is Not Enough and Wild Things, credited Muldoon for being 'always so humble' as she recounted their last times together.

'We hung out in the lounge waiting for luggage talking about what a fun weekend we all had, I haven't laughed that hard in a long time,' Richards said. 'We talked about plans of getting together & gave each other a hug and that was the last time.'

Richards and Muldoon, who shared the screen in the 1997 film Starship Troopers, had been romantically-linked for more than four years during the 1990s, and maintained a friendship in the years after.

The actress said that marking her late friend's birthday was a difficult task: 'I know you know, how hard it is for all of us. It's taken me all day to even post this... this is hard.'

Richards wrote that in the wake of Muldoon's passing, she continues to sense his presence.

'I feel you and see all your signs,' she said. 'Well I'm sure not all because these big ones show up, I laugh out loud hearing you say "Schweetbabe how do you not see what I've been putting in front of you?!? Now do you get it?"'

Richards recalled how her daughter Eloise, 15, had been fond of Muldoon when they were at the Los Angeles Comic Con event the prior year.

'A year ago today we were at the LA comic con and Eloise wouldn't leave your side... you had her giggling all day,' Richards said. 'She loved helping and watching you while you signed pictures and had everyone laughing.

'She was so happy being by you. She lit up today when I told her it's your bday and when I reminded her of last year she started laughing thinking about you.'

Richards said she never thought that the aforementioned event would be the last birthday she would see Muldoon.

'I love you so much schweetbabe... more than my best friend, my family,' Richards said. 'I'm so thankful I still have your family. And not a day goes by that I don't think about you. I know you're around I don't quite know where, but you're here.'

Richards said she had been 'beyond grateful' they were able to spend time with one another in Scotland and talk 'for hours about life,' adding, 'What a blessing and gift you gave me.'

She wrapped up in saying, 'Happy Birthday... as we would say... I miss you dearly & I dearly miss you Schweetbabe.'

The duo also appeared together in the film Dirty Hands, which came out on digital platforms April 24, shortly after Muldoon's passing.