President Donald Trump took a swing at a joke about his marriage to first lady Melania Trump on Tuesday — and her awkward reaction suggests it was a miss.

In remarks at a White House ceremony welcoming King Charles III and Queen Camilla to the U.S., the president remarked on his parents’ 63-year marriage before turning to his wife, who was seated between the royals.

“Excuse me, if you don’t mind. That’s a record we won’t be able to match, darling,” Trump said to the first lady, who cracked a stiff smile before turning toward the queen.

“I’m sorry. Just not going to work out that way. We’ll do well, but we’re not going to do that well, 63 years,” he continued.

Trump’s dark joke touches on his upcoming 80th birthday and the unlikelihood that he’ll live to see his 63rd anniversary in 2068, when he’d be 121 years old and his wife would be 97.