The makers of upcoming Telugu period-drama "Gauthamiputra Satakarni", which happens to be actor Nandamuri Balakrishna's 100th film, are yet to finalise a leading lady."While talks have been initiated with a few heroines including Nayanthara, the makers haven't finalised anyone yet. They are keen on roping in Nayanthara. However, she's preoccupied with prior commitment and hence might not have dates for the project," a source from the film's unit told IANS.However, she isn't ruled out yet."They plan to hold one last round of talks with her to see if she can manage to set aside dates for the project. Since she had already worked with Balakrishna in two successful projects, they feel she'll be his ideal pair," he said.Nayanthara and Balakrishna had previously worked in "Simhaa" and "Sri Rama Rajyam"."Gauthamiputra Satakarni" will be directed by National Award-winning filmmaker Krish.