AceShowbiz -

Liam Hemsworth is hooking up with his "Independence Day: Resurgence" co-star Maika Monroe, Us Weekly reports. A source tells the site that the pair were spotted "making out" at a Fourth of July party thrown by director Roland Emmerich.

"His hand was on her butt as she was grinding into him and they were making out at the bar," an eyewitness at the Hollywood party, which was also attended by Vivica A. Fox, Bill Pullman and Lance Bass, says of Liam and Maika. "Liam was draped all over her. It was so PDA and in-your-face!"

Another source claims Liam and Maika "are not official [yet], but their chemistry is ridiculous!"

The rumored couple was spotted picking up drinks and snacks together in Malibu on Tuesday, July 7. "The Hunger Games" actor and the star of "The 5th Wave" looked relaxed as they walked side-by-side, barefooted from the cafe. Liam was seen wearing black aviator, hoodie and grey shorts while Maika sported brown sunglasses, a black sweater and hotpants.

Liam was previously linked to Miley Cyrus after they met on the set of "The Last Song" in 2009. They got engaged in June 2012 and later called it quits in 2013. Miley is currently dating Victoria's Secret Angel Stella Maxwell following her split from Patrick Schwarzenegger.