But ahead of their big day - when Michael will turn 79 and Catherine 54 - they have another reason to celebrate.
The Basic Instinct actor has just been nominated for a coveted award, putting his dashing good looks front and center.
On Wednesday, it was announced that Michael is nominated for People Magazine's Sexiest Grandpa Alive award in its popular Readers' Choice poll.
The stars will have to wait until November 8 when the winners will be revealed.
Michael - who has won his fair share of 'sexiest men' awards over his decorated and lengthy career - is a doting grandpa to his two grandchildren, Lua, six, and Ryder, three.
His oldest son, Cameron, shares his children with long-time girlfriend, Viviane Thibes, and says Michael and Catherine adore being grandparents.
"I think they're enjoying them just as much as I am," Cameron told People of his dad's relationship with his grandkids.
"I've been spending a lot of time with them and it's fun being the grandparent, right? Because you don't really have to deal with the disciplining or any of that stuff, you just spoil them and have fun with them."
Michael and Catherine's children, Carys, 20, and Dylan, 23, are hands-on too.
Cameron continued: "They love spending time with both of their grandparents and all their uncles and aunts. It's really nice that everybody's been able to spend a lot of time together because it can be difficult when people are living all over the place. Time goes by quickly."
Cameron's mom is Diandra Luker, who split from Michael in 1995. She also has three other children from another relationship. With his children all grown up, Michael previously confessed to US Weekly that it makes being a grandparent that much more special.
"I was telling [Cameron], I love Lua, she's gorgeous. Grandchildren are great when you're an empty-nester and you don't have anybody and then you've got a grandkid - but when you still have kids in the house, it's like, 'Oh, OK. Great."
Michael earned a name for himself as a sex symbol in the 90s and he confessed to UK radio station Heart, he didn't think he would still be in front of the camera at his age. But he feels fortunate that there are roles for him despite battling ageism.
"Ageism affects us all [not just women] but I don’t think it’s as dramatic [for men]," he said."You know guys get to mellow as we get older, whereas women maybe seem under a little more pressure in terms of how they’re seen. But you know as long as there are parts for older actors, I’ll be around."
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