Gary Barlow shares rare photo of son Daniel – and look how tall he is!

Gary Barlow often keeps his personal life out of the spotlight, but on Tuesday he made a heartfelt tribute to his eldest son, Daniel.INSIDE: 8 epic celebrity man caves where Joe Swash, David Beckham and Eamonn Holmes escape from it allThe Take That star took to Instagram to mark the birthday of Daniel and he shared a photo of the pair together on the beach standing shoulder to shoulder. The 22-year-old towered over his father by a full head as the pair embraced each other while looking out to the sea.

"Happy 22nd Birthday to our Dan. We love you mate and you make us so proud every day," Gary wrote.WATCH: Gary Barlow works out with Daniel at homeWhile many were quick to wish Daniel a happy birthday, many commented on his height, as one joked: "Big Dan is a unit! He could be a super hero."SEE: Gary Barlow delights fans with rare snap of wife Dawn for this special reasonMORE: Gary Barlow stuns fans with beautiful picture of 'cute' wife DawnA second said: "I guess you know how Mark feels in the group," while a third posted: "Aw what a fab photo, happy birthday to Dan #heshuge."A fourth teased: "Are you kneeling? HAPPY BDAY DAN!" while a fifth simply added: "So tall."Last month, Gary gave his fans an intimate glimpse into his personal life by sharing pictures from his family holiday, which also happened to fall on his wife Dawn's 52nd birthday – and they looked completely besotted together! Fans were stunned at Daniel's heightAfter marking her birthday on Thursday, Gary shared a few more snapshots – taken by their son Daniel - from their sun-soaked family break.