Justin Timberlake stopped by the Tonight Show to talk about some rather interesting topics. The actor sat down with Jay Leno to talk about his new movie Bad Teacher and more surprising, being the father of Lady Gaga's child.  In the first part of the interview, Justin displayed his comedic side with jokes about the aches and pains that come along with turning the big 3-0.

In the second part of the interview, Justin fans are treated to a clip of Justin's latest video with Lady Gaga. The star also chats about what it was like filming sex scenes with actress Mila Kunis.

Moving on to more important things, Justin and Jay get down to business and discuss Bad Teacher.  Justin stars alongside Cameron Diaz in the comedy, and he had nothing but nice things to say about his ex-girlfriend.

What do you think of Justin's Tonight Show appearance?