Emma Roberts and Evan Peters arrive at the InStyle and Warner Bros. Golden Globe partyon January 13, 2013. Credit: Gregg DeGuire/WireImage

Emma Roberts and Evan Peters have kept a low-profile since they began dating in the spring of 2012, but that all changed after the 70th Annual Golden Globes in Beverly Hills Jan. 13.

The couple, who costarred in the movie Adult World, walked their first joint red carpet at the InStyle and Warner Bros. afterparty. Roberts, 21, looked ladylike in a corseted tulle dress, while Peters, 25, cleaned up in a three-piece suit.

Later that evening, the Scream 4 actress and the American Horror Story: Asylum actor were seen "making out" at Sunset Tower, a source tells Us Weekly. "At one point Evan was sitting on Emma's lap as a joke."

Roberts -- whose ex-boyfriends include Chord Overstreet and Alex Pettyfer -- is "so in love" with Peters, an insider reveals. "Evan dotes on Emma -- he's always holding her hand. . . They are super cute together!"

Says a Roberts source, "I've never seen her so happy with a guy. . . Emma and Evan really support each other, one hundred percent."