Mumbai, Dec 26 : Bollywood producer-director Karan Johar, who received good response to his film 'Rocky Aur Rani Kii Prem Kahaani' has said that his 'student' Alia Bhatt's true launch was with the Imtiaz Ali directorial 'Highway'. On Tuesday, KJo took to his Instagram and shared a picture of himself with Alia and Ranveer Singh, who served as the lead pair on 'Rocky Aur Rani Kii Prem Kahaani'. He heaped praises on Alia and Ranveer for their amazing performances. But, one thing that many people on the Internet resonated with was KJo calling 'Highway' the true launch of Alia. He penned a long note along with the picture, as he wrote: 'Before the year wraps, I felt like sharing this with all of you' I hadn't directed Alia since 2012 and the day she walked onto set In her @manishmalhotra05 plus @mickeycontractor plus #flavian look I knew we had the Rani I had always envisaged '. What followed was an actor I wasn't prepared for'. And I can take zero credit ' will always be grateful to Imtiaz Ali for taking her on a highway of life and moulding her into the actor she finally became. SOTY is technically her launch but her true launch as an artist will always be highway' Alia is such a pride and pleasure on a film set (sic).' 'She had a ticking mind constantly questioning Rani and trying her best to make her strong and yet identifiable and likeable ' again for that I take no credit that is her evolution as an artist! Was blessed to have her as Rani Chatterjee and I do hope her character keeps resonating '. Love you @aliaabhatt.' The director was also in awe of Ranveer, who he feels is a terrific performer. Heaping praise on Ranveer, he wrote, 'Ranveer Singh! The irreplaceable force of nature'. The actor prepares and never comes in your way ' he never ever let me know the extent he was prepping to play Rocky Randhawa' he planned his prep with my team , spent months in Delhi, hung out in west Delhi, met the West Delhi gram boys , worked on his dialect like an obsessed artist ! Kept improvising dialogues till it reached perfection for him.' 'I saw this as a bystander, a filmmaker in awe and was blown away by his process ( which initially can be daunting but when you see the dailies you're sold and he's won your heart) I feel like the perception of RS is so different from his labour and passion as a true artist! You see designer clothes on magazine covers I see a hungry actor only seeking love and validation from his audiences.' 'ROCKY RANDHWA and RANVEER were irreplaceable! (styled impeccably by @ekalakhani)No one could have done what he did! Absolutely No one and I feel grateful for him and Alia! The three of us also built a friendship for the ages as a trio! This is not just an appreciation post as a filmmaker but a post of gratitude to the universe that bought these blessed artists to play my leads! Karan Johar this side ' signing off! @aliaabhatt @ranveersingh #rockyaurranikiipremkahaani,' he added. 'Rocky Aur Rani Kii Prem Kahaani', which follows the story of two people in love coming from different worlds, marked KJo's return to direction 7 years after 'Ae Dil Hai Mushkil'. The film was released on July 28 and managed to perform well at the Indian box-office despite competition from global blockbusters like 'Oppenheimer' and 'Barbie'. /IANS