Mumbai, Sep 19 (IANS) His last release 'Shootout at Lokhandwala' was a huge success. Now director Apoorva Lakhia is readying to make a global espionage thriller 'Mission Istanbul'. But the film seems to be going through a lot of casting upheavals.

First it was Bobby Deol who opted out and was replaced by Zayed Khan. Then Tusshar Kapoor didn't have the required dates.

The latest rumour doing the rounds is that Sagarika Ghatge, who played Preeti Sabharwal in 'Chak De! India', has been signed to play one of the female leads in 'Mission Istanbul'.

'Not at all,' said Lakhia. 'I don't know where that rumour started. Sagarika isn't in 'Mission Istanbul'. The only female lead we've finalised is Shreya Saran (recently seen with Emran Hashmi in 'Awarapan'). The other girl is still to be finalised,' Lakhia told IANS.

So what's the cast of 'Mission Istanbul' so far?

'It's Zayed Khan, Suniel Shetty, Viviek Oberoi, Shabbir Ahluwaila, Shreya Sharan and newcomer Niketan Dheer, who is character-actor Pankaj Dheer's son and quite a discovery,' said Lakhia.

And contrary to scepticism, Abhishek Bachchan is putting in a guest appearance in the film.

'I have to have either Amitji (Amitabh Bachchan) or Abhishek, or preferably both in all my films,' said Lakhia, who made his directorial debut 'Mumbai Se Aaya Mera Dost' with Abhishek and teamed up with Amitabh in 'Ek Ajnabee'.