Filming for the Twilight series has wrapped, but Robert Pattinson and Kristen Stewart show no signs of slowing down.

The normally private pair were inseparable at his April 17 NYC premiere of Water for Elephants and shared a rare public smooch as they left the Le Cirque afterparty.

"They had a long, slow kiss," a witness tells the new Us Weekly (on stands now). "You could tell they'd been waiting all night. They were very affectionate."

After all, according to Donna Scott, Pattinson's Water for Elephants costar, "He is madly in love with her!" See more photos of Rob and Kristen making out.

Indeed. Just one week earlier, Pattinson, 24, stood by his girlfriend's side at Stewart's 21st birthday bash (which doubled as the Breaking Dawn wrap party) at Rockwell's Bar & Grill in Vancouver on April 9.

"They held hands, and he kissed her cheek," a source tells Us of the twosome, who were joined by costar Taylor Lautner and his girlfriend, Lily Collins.

And Stewart's gift -- a motorcycle form the cast and crew -- gave Pattinson another chance to dote. "Rob watched as she sat on it to make sure she was OK!" a source says.