Actor Zac Efron and his girlfriend Sami Miro attended the Treats!, an annual Halloween celebration at a theatre here.

The 27-year-old actor was spotted wearing a white mask as his partner Miro donned denim-on-denim for the Friday event, reports eonline.com.

According to a source, the duo looked happy together.

"They were acting very much in love, she kept hugging him, their love looked genuine," added the source.

Michelle Rodriguez, Leonardo DiCaprio, Ryan Seacrest, Robin Thicke, Paris Hilton and Derek Hough were also spotted at the event.