Usain Bolt's stunning girlfriend shares sweet snap of the sprint legend hand grabbing her bum as they celebrate his birthday

Sprint legend, Usain Bolt, turned 31 on Monday and his Jamaican model girlfriend, Kasi Bennet shared a sweet snap of the greatest sprinter of all time hand grabbing her bum and wrote:
'The Legend. Happiest of birthdays to the most humble, selfless, hardworking and motivating person I know. Every single day I feel like the luckiest woman to have you in my life. You are nothing short of amazing.
I love you baby, and remember... EVERY DAY WE LIT'