Bradley Cooper plays a mentally ill man who lives with his parents and Jennifer Lawrence a troubled widow in the deliciously entertaining Silver Linings Playbook, a drama-comedy that slowly and unexpectedly transforms into one of the sexiest and most romantic stories of the year.

Pat (Cooper) and Tiffany (Lawrence) meet one night and sparks immediately fly, but not in the way their friends intended. Pat, who suffers from bipolar disorder, is still obsessed with getting back together with his estranged wife, while Tiffany has spent the last year trying to suppress her grief by sleeping with everyone she encounters. Naturally, they hate each other. Over time, however, the two become unlikely friends, even though their motives are often at conflict.

Robert De Niro and Jacki Weaver play Pat's parents, who have their own set of issues.

Both Cooper and Lawrence deliver exceptional performances, both worthy of Oscar nominations. Cooper pushes his character's frenetic, temperamental disposition to a line that, if crossed, would have made Pat unlikable and obnoxious. Instead, he pulls back at just the right moments to craft one of the more complex, entertaining and memorable characters of the year.

Lawrence was very good in Winter's Bone (for which she received her first Oscar nomination) and effective in The Hunger Games, but I didn't understand what all the hype was about until Silver Linings Playbook. Not only is her character about as sexy as any that have been onscreen all year, but she is raw emotional and pure energy. Lawrence turns in one of the best if not the best female performance of the year.

Beyond the acting, Silver Linings Playbook is superbly written and directed by David O. Russell (The Fighter), working off the novel by Matthew Quick. The screenplay is fast, energetic and packed with tasty dialogue.

The film only falters in one scene in the third act where all the characters converge for the first time in Pat's house, in which his father and friend make a serious gambling bet. For such an unconventional story, the scene feels strangely conventional, out of place and abrupt; it temporarily halts the story's flow and momentum.

Nonetheless, Silver Linings Playbook is a terrific movie and unexpectedly romantic. Featuring great performances and a sharp screenplay, it is one of the most pleasant and profound surprises of 2012.

Review by Erik Samdahl unless otherwise indicated.