Is life about to imitate art on the set of Friends With Benefits? Justin Timberlake is falling for Mila Kunis, his sexy costar on the currently-shooting flick, multiple insiders tell Us. "He is absolutely obsessed with Mila," a pal says. Adds another: "He's smitten!"

Find out how Timberlake could stray -- again -- from longtime love Jessica Biel in this week's Hot Stuff video.

The roundup -- hosted by Senior Editor Ian Drew and his beautiful mom, Susan! -- also dishes on the escalating romance between Kate Hudson and rocker Matt Bellamy (he's ready to get married!), Justin Bieber's "hard" crush on Selena Gomez and more.

Catch up on all the scoops -- watch the video now (above)!