Things are heating up between singer Jason Derulo and “Gossip Girl” star Tika Sumpter. After the preview party for his new album, “Future History,” at the James Hotel the other night, the pop star and Sumpter headed to 1Oak, where a spy said they were “making out in front of everyone.” Sumpter didn’t attend the bash at the rooftop of the hotel earlier that night, where Derulo presented his new tracks to guests. Sumpter stars in Derulo’s new video, “It Girl,” and the two were spotted on a frozen-yogurt date last week in LA.