Zac Efron was spotted back in the Hollywood scene last Thursday night at one of H.Wood group's hot spots, Blind Dragon, located in West Hollywood.

The 27-year old actor dropped by the popular hotspot but instead of simply grabbing some food to eat and leaving, he stayed a while and spent the night partying with his friends and girlfriend, Sami Miró.

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That Awkward Moment star, along with his friends, arrived at around 11:15 in the evening and stayed in one of the night club's private karaoke rooms, where the star, who shot to fame in High School Musical, reminded everyone of his impressive vocal skills.

An eyewitness told People that the actor stood on the sofa inside the room, had one of the microphones and sang Smashmouth's hit All Star and Sugar Ray's Fly.

Though it was clear that Zac was enjoying the party, one thing he was not doing was drinking alcohol. The actor, who checked himself into rehab in May 2013 and finished the program in September of the same year, enjoyed an interesting evening of clean and sober fun.

The source added that Zac appeared "to be in really good spirits. He was not drinking and was getting a kick out of karaoke."

His night turned out to be even better when his girlfriend finally arrived and joined his friends at Blind Dragon, a few minutes after 1 am.

An onlooker revealed that Zac was extremely affectionate toward her and had his hand on her back while they mingled with their friends.

"They even shared a few brief kisses" and added that although they "stuck to the people they knew," the sweet couple still let loose. 

The couple and their friends reportedly stayed until the club closed.

The very private couple has always tried to keep their relationship under wraps, but that proves to be tricky especially when your main man is Zac.

In a previous interview with Elle.com, Sam was asked about her highly speculated yet successful romance with Zac and simply said that it's about putting yourself in the other person's shoes and understanding where he's coming from.

Once you successfully do so, then that's when everything "kind of makes sense," she said.

TagsZac Efron, Sami Miro, Blind Dragon, West Hollywood