Neil Patrick Harris and David Burtka celebrate 20 years together

Neil Patrick Harris and David Burtka have defied Hollywood odds with their long-lasting marriage.

The How I Met Your Mother star took to Instagram to share the couple's 20-year love story.

“Our first date was 20 years ago today. Man, how time has flown by… and yet… we’ve shared so many adventures, created so many remarkable memories,” wrote Harris.

“If the next 7,300 days are like the previous ones, I’ll be absolutely thrilled. Happy anniversary, David. I love you unconditionally, most of the time. XO,” he quipped.

The charming message, reported in the Daily Mail, was accompanied by a recent picture of him and Burtka, side by side.

The comments were flooded with warm messages, including from Selena Gomez, who posted a crying emoji and a heart.

The actors met when they were both on Broadway, with Harris in Cabaret and Burtka in Gypsy.

“I was invited to an American Idol viewing party — I just stammered around him. I couldn’t take my eyes off him,” Harris explained to Out in 2012.

The twosome began dating in 2004 and started their family in October 2010, welcoming fraternal twins Gideon Scott and Harper Grace via surrogate.

Harris and Burtka tied the knot in 2014.