Catherine Zeta-Jones often shows the world how much she loves her husband Michael Douglas with public messages of affection, and the Welsh beauty didn't miss the opportunity to do the same for her father-in-law Kirk Douglas when the star celebrated his 99th birthday on Wednesday.
"Happy Birthday to my dearest Father in Law, Kirk. 99 years young today. I love you with all my heart," wrote the actress alongside a black-and-white image of the duo on Instagram. The snap captured Catherine, 46, dressed in a lace dress kissing the suited Oscar-winning actor tenderly on the cheek.
Meanwhile, Michael was understandably delighted at seeing his father reach the milestone age.
The Wall Street actor paid tribute to his father in a sweet photo showing the pair embracing. He wrote: "Happy 99th Birthday Dad! I love you, Michael".
Kirk Douglas turned 99 years old on Wednesday
Born in 1916, Kirk rose to fame in the Forties and has since become a Hollywood veteran, starring in an impressive list of blockbusters, including Spartacus and The Bad And The Beautiful. Michael, 71, starred in It Runs In The Family with his dad and son Cameron in 2003.
The star married Diana Douglas in 1943. The couple had two sons together, Michael and his brother Joel, before divorcing in 1951. The actress, who was Kirk's first wife, sadly passed away at the age of 92 in July after a battle with cancer.
Kirk starred in Spartacus in 1960
Michael, who celebrated 15 years of marriage with Catherine in November, has been getting ready for his dad's special birthday for a few days. The Basic Instinct star shared a fun throwback photo of his dad acting in Spartacus. He wrote: "#ThrowbackThursday Can you believe my dad is going to be 99 next week? #tbt"
The father and son are a close pair and became even tighter when Michael overcame cancer in 2014.
"I admire the way Michael has handled this personal crisis. He was open and honest with his family, the media and the public," the screen icon told People. "He was gracious throughout, trying to live a normal life despite the constant press scrutiny and daily treatment."