Bollywood actor Akshay Kumar says actress-wife Twinkle Khanna, who turned 38 Sunday, is the "best thing" in his life.

"There's really no contest when it comes to the best thing in my life. It's you! You are the reason why I smile during good times. But more importantly you are the reason why I smile even during bad times.

Happy birthday Tina! And guys thank you for all your sweet wishes for my wife, shall pass them onto her," Akshay tweeted Sunday.

Twinkle shares her birthday with her superstar-father Rajesh Khanna, who died July 18, 2012.