Actress Kajol has wished her "Eela" co-star Riddhi Sen on his 20th birthday on Saturday and said he should fly strong, straight and true always in his career.Kajol tweeted a selfie along with Riddhi and captioned it: "Happy birthday Riddhi Sen. Last day on our shoot... First day of your new play 'The Starry Night' ('Taraye Taraye'). Hope you fly strong, straight and true always. Thank you for everything!"Kajol and Riddhi will be seen in the tentatively titled film "Eela", which is slated to release on September 14.The film is directed by Pradeep Sarkar and will have the National Award winning actor playing Kajol's son.Written by Mitesh Shah, "Eela" will see Kajol playing a single mother and an aspiring singer.The movie is co-produced by Ajay Devgn and Jayantilal Gada of Pen India Ltd.Kajol was last seen on screen in "VIP 2", a Tamil-language comedy-drama film directed by Soundarya Rajnikanth. She played an antagonist.It was a sequel to the 2014 film "Velaiilla Pattadhari". "VIP 2" also features Dhanush, Amala Paul, Vivek, Hrishikesh, Saranya Ponvannan and Samuthirakani.