Ryan O'Neal's 'Lifestyle Caught Up With Him' After He Died of Heart Failure: 'He Spent Years Partying'

Hollywood star Ryan O'Neal died of "congestive heart failure," according to his death certificate, which is why his inner circle is not surprised about the cause of death due to him not always taking care of his body.

"Ryan's lifestyle caught up with him. He spent years partying and all those drugs weakened his heart. It's amazing he lasted as long as he did," a pal told an outlet about the actor, who died at 82 years old on December 8.

The Peyton Place lead dealt with several health issues before his passing: he was diagnosed with chronic leukemia in 2001 and prostate cancer in 2012.

After the news got out, his daughter Tatum O'Neal — whom Ryan starred alongside in Paper Moon and had a complicated relationship with — only had kind words to say about her father.

"I feel great sorrow with my father's passing," she told People in a statement. "He meant the world to me. I loved him very much and know he loved me too. I'll miss him forever and I feel very lucky that we ended on such good terms."

Meanwhile, Ryan's son Patrick O'Neal wrote a touching tribute to his father.

"Ryan was a very generous man who has always been there to help his loved ones for decade upon decade. Those same people are heartbroken today and will be for a long time. My everlasting thanks to his team. Our team. Marly you are so special to Ryan. You have been with our family for 39 years. Needed you every day. Greg and Melanie thank you for your care and friendship with my dad. I’m so sorry. Hart having you with me by my side was so important for me. And you. Alexandra. You are a true champion. Thank you so much. You are family. Dr. Piro thank you for your love and care for my father. You have quite a history together. There are many many many others who my father touched. And who love him. This is just so hard for us," he admitted.

"Ryan made such an impact and this will be difficult without him. This is and will be a huge void in our lives. And his dogs Mozart and Raven, who he loved dearly, are missing him very much. They were inseparable.I will share my father’s legacy forever. I will not be deterred from outside voices that say negative things. If you choose to talk shit about my dad, even though you have no clue what you are talking about, you will get called out. If you go that route, I recommend you take a good look in the mirror first. My dad was 82, and lived a kick a-- life," he continued.

Patrick also noted how Ryan, who is now buried next to his longtime lover Farrah Fawcett at Westwood Memorial Park Cemetery in Los Angeles, Calif., will be reunited with the late actress.

"But he has bragging rights in Heaven. Especially when it comes to Farrah. Everyone had the poster, he had the real McCoy. And now they meet again. Farrah and Ryan. He has missed her terribly. What an embrace that must be. Together again. I’ll miss you dad. I love you. We love you. No one told a story better than Ryan O’Neal," he concluded.

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Daily Mail spoke to the insider.