It was a steep relationship trajectory for Alex Pettyfer and Dianna Agron. In early February, just days before the release of their film, "I am Number Four," the cohabiting twosome were hit with engagement speculation. By the end of the month, they were kaput amid rumors that the supposedly hotheaded actor had a furious confrontation with "Gossip Girl" actor Sebastian Stan at a Los Angeles club. Word is, Pettyfer accused Stan of cozying up to the "Glee" starlet. And it turns out he may have been onto something. Within months, Agron and Stan were coupled up, although their bi-coastal relationship had cooled off by December.