{blackbabes} Bradley Cooper & Zoe Saldana Share Kisses at Sundance

Castmates and rumored off-screen couple Bradley Cooper and Zoe Saldana weren't coy about their relationship status at Sundance! The costars were spotted taking their romance public, smooching at a cocktail party for their film The Words at the Park City, Utah, film festival.

"They were kissing in front of the fire and being very affectionate," an onlooker tells us of the pair, who so far have been silent about their budding romance. Adds a source: "They are definitely very together."

Another onlooker at the party says that the pair were caught in an intense conversation and were giggling, with Saldana touching Cooper's arm as he told a story before they retreated to a couch together. Adds the onlooker: "They were like two seventh graders. The electricity was out of this world."

The night before their PDA-filled party at Montage Deer Valley, the two attended an Acura-hosted premiere dinner together. The private party drew about 50 people, just castmembers and close friends of the actors, and Saldana and Cooper were spotted interacting with everyone at the dinner. Everyone was laughing a lot, a source says, and people were dancing as a deejay spun tunes.