'Alone': Bipasha Basu, Karan Singh Grover at their Boldest in Steamy 'Katra' Song [VIDEO]

After the super scary "Alone" trailer, the makers have now released the extremely sensuous 'Katra' song featuring Bipasha Basu and debutant Karan Singh Grover.

Sung by Prakriti Kakkar and Ankit Tiwari, the song in itself is near-average but the video turns up massive heat and is a testimony to the lead pair's sizzling chemistry.

Directed by Bhushan Patel, the film belongs to the horror genre but at its core is a love story between a man, woman and a spirit. "It's a passionate love story. It is definitely a horror genre and will scare you, but it revolves around a love story... a love story between a man, a woman and a ghost," IANS quoted the actress as saying. The Bengali beauty also added that it would definitely be her boldest film ever.

Laced with intimate, steamy scenes, the video was reportedly shot with a small crew as Basu was conscious of getting filmed amid a massive backstage team.

In other news, the onscreen pair has been appreciated by many for the kind of chemistry they have displayed. While they have rubbished rumours of a possible affair, Grover stated that it was their 'natural ease' which worked for them.

"There is no real secret behind the said electric chemistry between the two of us. We've stayed true to the script and what worked was our natural ease. I have played the romantic hero always and hence a certain zest comes naturally to me," The Times of India quoted the suave actor as saying.

Known for his charm and wit, the actor also added, "It's great that my job entails making out with a hot lady and even getting paid to do that (winks)."

Slated for a 16 January, 2015 release, the film's trailer has already garnered close to 4 million views on YouTube and has been lauded by bigwigs from the Hindi film industry.

Watch the song video here: