"This was taken at your mom's house 20 years ago. That's a long time ago!!! So I decided to do some math…,” he wrote alongside it.
Alongside an old photograph of them together, the 46-year-old actor wrote: ''This was taken at your mom's house 20 years ago. That's a long time ago!!! So I decided to do some math... I have sung happy birthday to you 20 times and I have bought you 19 birthday presents (I was mad that one year). I have watched you blow out 693 candles (737 after tonite). I've told you 'I love you' at least 8,285 times. And of the nearly 3.96 Billion women on the planet - there is only 1 that I want to spend the rest of my life with. Happy Birthday, my Love! (sic)''
The touching message comes just over one month after Will blasted rumours his marriage to the 'Magic Mike XXL' actress, with whom he has son Jaden, 17, and daughter Willow, 14, was on the rocks on his Facebook profile.