Mega-celebrations are being planned for megastar Amitabh Bachchan's 70th birthday Oct 11. Designer duo Abu Jani and Sandeep Khosla are assisting the veteran actor's wife Jaya in creating a "big surprise", and they are even designing a special outfit for Big B.

"It is a big surprise. I can't reveal everything right now. We are designing something special for Mr. Bachchan. You will get to know about everything as you get closer to the big day. Things will get clearer as we will get closer to the event," Khosla told.

The designer duo has been creating outfits for the Bachchan family - Amitabh, Jaya, Abhishek, Aishwarya and Shweta Nanda - since long, and their association goes much beyond just clothes. Amitabh recently launched their book in London, along with Hollywood star Judi Dench.

As for the much awaited birthday bash, Khosla remained tight-lipped, but said: "It will be Jaya Bachchan's event. We will only be helping her with all the preparations. Individually, we are not hosting any party for him."