Uday, 33, was found hanging from the ceiling in his flat.
Here's what they had to say:
Music composer RP Patnaik: Uday, you should not have done that. You still have many fans who like you for what you are. There was still a career to move on. Committing suicide is not a solution for a struggle. You should have fought till the audience realised that you are a self-made star. Our songs have been all-time superhits. You will remain in the hearts of the people forever.
Vimala Raman: RIP (rest in peace), Uday Kiran my first co-star in my career and a sweetheart. You will be missed.
Priyamani: (I) woke up to hear the news of Uday Kiran! RIP Uday! One of the nicest and friendliest guys I know. Deeply saddened by the news!
Prakash Raj: (I'm) extremely disturbed with the news of young actor Uday Kiran's suicide. What was wrong young man? Sad! Shouldn't we find reasons to live?
Vennela Kishore: (I'm) shocked and feeling terrible by the news about Uday Kiran ending his life. What he must've gone through to take such a step? Cruel pressure.
Sundeep Kishan: (I'm) Shocked. Uday Kiran is no more. (He) was such a warm and nice person. (It's a) depressing news. RIP brother. Strength to his family.
Kiccha Sudeep: Uday Kiran's news is a shocker; (I) was unable to react when I got the news. (I) spoke to him when he was here at Bangalore less than a week back. RIP my friend!
Khushbu Sundar: (I'm) shocked to hear that a young and talented Uday Kiran is no more among us. (The) worst you can do to yourself and your loved ones is to commit suicide. RIP.
Varun Sandesh: (I'm) very sad that Uday Kiran is no more. (He was) such a young chap (and) a very sweet and a kind-hearted guy. (I) still can't believe it.
Gopi Mohan: (This is) very bad news about Uday Kiran's suicide. We did Nuvvu Nenu film (together). Teja (director) made him a star. He was a nice guy. (It's a) very sad news to hear in the morning.