But commenters have flooded the post with tongue-in-cheek well-wishes confusing Krokdal with one of Lundgren's two daughters, aged 19 and 24.
"Your daughter got engaged? Good on ya Dolph," wrote one person under the photo.
"Congrats to your daughter and partner," said another.
"Dolph you have a commanding presence..... and your daughter looks lovely," said a third.
"Congrats to your daughter!!! Who's the lucky guy?" wrote another.
"You married your daughter?" asked another.
Leave it to Lundgren's former Rocky co-star Sylvester Stallone to offer genuine well-wishes: "Congratulations my good friend. You're the best," he wrote.
After high-profile relationships with singer Grace Jones and American model Paula Barbieri in the 1980s, Lundgren married jewellery designer Anette Qviberg, nine years his junior, in 1994. The couple had two daughters before divorcing in 2011.
Lundgren's engagement news comes as another actor wed his much younger fiance this month: Actor Dennis Quaid, 66, and his fiance Laura Savoie, 27, were married at a seaside resort on June 2, People magazine reported. Quaid previously said it was never his intention to find someone Savoie's age.
"I didn't go out looking for an age gap or someone really younger than me," he explained. "I met her at a business event and then the relationship developed.
"You have no control over who you fall in love with," he continued. "I don't fall in love easily. But I can't let what a few people think control all that. I've been married three times and this is the final one, I know it is. I feel like I have a real partner in life."
