Vanessa Hudgens & Austin Butler Kiss 'Non-Stop' While Partying in Las Vegas
05/16/2013 AT 07:30 PM EDT
The pair, who kicked off Saturday night by dining at new hotspot Hakkasan Las Vegas were joined by Kelsey Grammer and wife Kayte Walsh, who were all celebrating a mutual pal's birthday.
In a nearby private dining room was Ke$ha, who threw a surprise party for one of her creative directors.
When Hudgens's table was done eating, her group then gathered in the main room of the venue's nightclub, where they sat at a VIP table next to the deejay booth – and her PDA with Butler began.
"The couple was very cute together," an onlooker tells PEOPLE, of the black mini-dress-clad actress and her The Carrie Diaries beau. "They were seen dancing a lot throughout the night. They were sipping on cocktails and being cuddly and affectionate and were spotted kissing non-stop throughout the evening. They were listening to the Bingo Players, who deejayed that night."
– Dahvi Shira