Jason LaVeris/FilmMagic; AP Photo / Tammie Arroyo 
 
 She's 18. He's 36. 
 
 But the laws of celebrity attraction apparently knew no boundaries when it came to Demi Lovato secretly connecting with her most recent boyfriend...Ryan Phillippe! 
 
 MORE: Ryan Phillippe's Pregnant Ex: I Don't Need His Help! 
 
 E! News has learned exclusively that Lovato has been quietly dating Phillippe, the actor and divorced dad of three (including 2-week-old daughter Kai with ex-girlfriend Alexis Knapp), over the last couple of months. 
 
 A source says Phillippe and Lovato started seeing each other casually, but it quickly heated up, with the source revealing that things have cooled a bit since the birth of Phillippe's daughter. 
 
 "It was really hot and heavy for a while," says a source close to the casual couple, adding that Lovato didn't know for sure that Phillippe was going to be a father again "until it basically happened. It kind of threw her for a loop." 
 
 But the reason for slowing things down with the former Mr. Reese Witherspoon wasn't all about the new baby, but also about Lovato's baby of her own. The promotion of her new single "Skyscraper" and video, which premiered last week on E! News, has been consuming most of her attention in the last few weeks. 
 
 In other words, only time will tell if these two will eventually evolve into a full-fledged item. 
 
 Reps for the stars have not yet responded to E! News' request for comment, though a source close to Phillippe denies that any relationship with Lovato took place and says that the actor is currently "totally single." 
 
 (Originally published July 18, 2011 at 11:18 a.m. PT) 
 
 WATCH: Demi Lovato Opens Up About Addictions ||||| Is Demi Lovato, 18, Hooking Up With Ryan Phillippe, 36? 
 
 He may be twice her age, but according to E! News, that didn't stop Ryan Phillippe, 36, from hooking up with Demi Lovato, 18. 
 
 "It was really hot and heavy for a while," a source tells the site. 
 
 PHOTOS: More May/December romances 
 
 An insider confirms the news to Us Weekly, pointing out that "they were just hooking up" and "it was nothing serious." 
 
 PHOTOS: Shocking celebrity hookups 
 
 E! News adds that the "Skyscraper" singer didn't know the Lincoln Lawyer actor was going to be a father again "until it basically happened. It kind of threw her for a loop." 
 
 (Phillippe's ex-girlfriend Alexis Knapp welcomed daughter Kai at L.A.'s Cedars-Sinai Medical Center on July 1; the actor has yet to take a DNA test to prove his paternity. Phillippe also has two children -- Ava, 11, and Deacon, 7 -- from his first marriage to Reese Witherspoon.) 
 
 PHOTOS: Ryan and other hunky, shirtless dads 
 
 After seven months together, Phillippe split with on-off girlfriend Amanda Seyfriend in June 2011. Lovato's past loves include Wilmer Valderrama, Joe Jonas and Trace Cyrus.
– He's twice her age, but when has that ever mattered in Hollywood? Ryan Phillippe, 36, is apparently hooking up with troubled Disney starlet Demi Lovato, 18. The two have been secretly dating for months, a source tells E!, adding that "it was really hot and heavy" until Phillippe's daughter with an ex-girlfriend was born two weeks ago, which "kind of threw [Lovato] for a loop." Another insider tells Us the two "were just hooking up," not engaging in anything "serious." TMI alert: Phillippe's eldest, daughter Ava, is just seven years younger than Lovato.