The song featuring Sunny is called "Seshamma seshamma".
"She has been shooting with us for the last three days at a set specially erected for the song. We are likely to finish shooting the song today (Monday). It's a folk song and audiences are sure going to enjoy seeing Sunny groove to it," a source from the film's unit told IANS.
"We've been shooting the song secretly as we didn't want Sunny's presence in the city to attract public attention," the source added.
"DK", which is directed by Udaya Prakash, features Prem in the lead role.
Sunny was recently seen in a special song for Tamil film "Vadacurry", while she also completed shooting an item number for upcoming Telugu film "Current Theega" as well.