The star couple, who got married in 2012 after a long courtship, older son, Riaan, was born on November 25, 2014.
Riteish, who is currently busy promoting his upcoming comic caper Housefull 3, took to Twitter and announced the good news in the most adorable way.
He posted a picture of Riaan and wrote, 'Hey guys, my Aai & Baba just gifted me a little brother. Now all my toys are his... Love Riaan.'
As soon as the happy father broke the news on Twitter, Riteish and Genelia's friends from the industry congratulated them on the social media site.
Karan Johar: 'Huge congratulations @Riteishd @geneliad .....a baby boy!!!! Sending you both all my love and the best years ahead.'
Punit Malhotra: 'Many congratulations!! Wish you'll all the love in the world! @geneliad.'
Arpita Khan Sharma: 'Congratulations guys @Riteishd @geneliad can't wait to see the lil one..Super excited ?big hug to all & lots of love.'
Shruti Seth: 'Congratulations @Riteishd @geneliad...Lots of love to the new arrival and to his big brother.'
Satish Kaushik: 'Congrats @Riteishd @geneliad for another beautiful addition to the family..'
PIX: Riteish and Genelia's church wedding
Genelia's STYLISH pregnant pictures!
PIX: Genelia, Arpita and Kanchi flaunt their baby bumps!
PIX: Riteish and Genelia's star-studded pre-wedding bash
PIX: Stars arrive for Riteish-Genelia wedding