The snaps show their family home decorated with large shiny balloons and bunting to mark the special milestone. "Happiest 21st birthday Dan," the doting dad wrote alongside a series of heart emojis.
WATCH: Gary Barlow works out at home with his son Daniel
The birthday comes almost one month after the Barlow family pulled out all the stops for Dawn on her 51st birthday. Taking to his Instagram Stories, the singer uploaded a series of photos – including a heartwarming tribute.
"Happy birthday Mrs B," he said, alongside a series of heart emojis. He then uploaded photos of their delicious meal, cooked by their daughters Emily, 19, and 12-year-old Daisy, and a beautiful cake topped with strawberries.
The latest posts were a welcome surprise as Gary tends to keep his family away from the spotlight.
One of the images Gary shared on social media on Monday
During a chat with Cosmopolitan UK, the 50-year-old confessed the couple tend to enjoy weekly tipples with one another. Asked about his guilty pleasure, Gary replied: "I like a drink. I really do. It's all under control - I don't want to lead anyone astray!
"My wife and I like to go for a very early drink on a Friday night. While we're enjoying our cocktails, we will catch up on the week. It's a nice excuse to do that."
The couple met back in 1995 when Dawn was working as a backup dancer on Take That's Nobody Else tour. They tied the knot five years later, and have since become loving parents to their three children; Daniel, 20, Emily and Daisy. Sadly, their fourth child, daughter Poppy, was stillborn in 2012.
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