The Rowdy Rathore star once had a relationship with Shetty and was reportedly engaged to her.
"It is a very good news. I hope everyone is healthy and happy and they remain so ever," Kumar told
Shetty gave birth to a baby boy at Hinduja hospital yesterday morning (May 21), with her businessman husband Raj Kundra breaking the good news on Twitter soon afterwards.
The 36-year-old actress also tweeted: "Can't believe am a mother now! Ecstatic is an understatement. Thank you so much for all the good wishes and love all of you have bestowed us and Baby K."
Following Kumar and Shetty's much-publicised break-up, he married Twinkle Khanna in 2001 and has an 11-year old son Aarav. The couple are now expecting their second child.
Shetty tied the knot with London-based businessman Raj Kundra in 2009.