Urban posted a photo of his own of a table full of gifts, balloons and roses with Kidman, 52, peeking out from behind the goodies.
"Thank you to EVERYONE for all the birthday love !!!!!!!!! (it’s all in the details)," he wrote.
The couple began celebrations early for Urban's birthday, taking a trip together to Italy.
Kidman and Urban married in their native Australia in June 2006.
The pair share daughters Sunday Rose, 11, and Faith Margaret, 8.
Earlier this year, Kidman told a heartwarming story of the moment she knew that Urban was the one she wanted to marry.
Speaking to People, the star talked about a time in 2005 shortly after she met Urban at an event in Los Angeles. The duo grew closer in the following months. Then the country singer made a grand, romantic gesture to prove his affection.
“It was my [38th] birthday, and he stood outside with gardenias at 5 a.m. on my stoop in New York,” she told the outlet. “That is when I went, ‘This is the man I hope I get to marry.’”
Fox News' Mariah Haas contributed to this report.