Rajnikanth, Dilip Kumar and Shah Rukh Khan were among the 800 guests who attended the event in Mumbai's Film City, NDTV Movies reports.
Wearing a black velvet suit, Amitabh arrived at the event with wife Jaya Bachchan, son Abhishek, daughter Shweta and daughter-in-law Aishwarya Rai.
Speaking from the red carpet with wife Aishwarya, Abhishek Bachchan said: "It's a very big day for us. The greatest gift for my dad is to see all his friends show up. He's so excited. He's like a child you know. He's so excited that everybody's come and he's really happy that you all are here."
Walking the red carpet to the strains of a band playing songs from his films, Amitabh thanked the media for attending the event. Aishwarya said: "We are so happy that we are all here today celebrating his birthday. Thank you so much."
Speaking to press, South Indian star Rajnikanth said: "I pray to God and wish for him a long life and good health."
Veteran actress Waheeda Rehman said: "[Bachchan is] one of our greatest actors. I am very proud of him."
Many of Amitabh's former co-stars attended, including veteran actors Hema Malini, Saira Banu, Waheeda Rehman, Vinod Khanna, Prem Chopra, Kader Khan, Pran, Zeenat Aman, Jeetendra, Asha Parekh, Neetu Singh, Rishi Kapoor and Shashi Kapoor, who starred with Bachchan in Deewar.
Shabana Azmi, who starred in Amar Akbar Anthony with the actor, described him as an "iconic figure" adding: "I got an opportunity to work with him. He is my favourite."
Madhuri Dixit said she wished him all the "happiness and success", while Vidya Balan, who played Amitabh's mother in Paa, described the veteran actor as "an inspiration, not only for actors but for everyone".
Having attended the event with wife Gauri, Shah Rukh Khan tweeted about the party the next morning, saying: "Danced with Amitji & Jaya aunty to all the songs i have grown up listening. Too much fun. Thanx abhishek,aishwarya & Aaradhya for the warmth."
The actor's birthday was also marked by an art exhibition featuring paintings inspired by Bachchan's life and career.
Widely regarded as the biggest star of Indian cinema, Amitabh Bachchan turns 70 today (October 11).