Miley Cyrus and Patrick Schwarzenegger Ring in 2015 With Newly Engaged Sofía Vergara and Joe Manganiello!

Miley Cyrus and Patrick Schwarzenegger are starting 2015 with a whole lot of love!

The young Hollywood couple headed to Las Vegas over the holiday to kick off the new year with a bang as they celebrated with family and some surprise friends.

It all began with a fabulous dinner at Strip House Las Vegas inside the Planet Hollywood Resort & Casino where the pair were joined by newly engaged Sofía Vergara and Joe Manganiello as well as Arnold Schwarzenegger and his girlfriend Heather Milligan.

"Excited for the new year!!!!" the Modern Family star wrote on her Whosay page while posing with her fiancé and the Terminator star. "Wishing everyone a lot of work and happiness!!!)

She later shared a solo shot with just her main man and a caption, "Happy New Year!!!!! Feliz añooo."

After a tasty meal that included New York strip steak and black truffle creamed spinach and potato, the group headed to the sold-out Britney Spears concert at the same hotel.

"Sofia and Joe were very affectionate, holding hands and whispering in each other's ears the whole time," an eyewitness told E! News. Not to be outdone, Patrick and Miley also appeared to have a blast while sitting a few tables away from the pair.

"Miley danced the whole time and sang along," the eyewitness added. Patrick even got a midnight kiss after a night of non-stop hits. "2015," the "Party in the U.S.A." darling shared in her first Instagram post that included her new man!

And what could be the cherry on top to a fabulous night? Everyone got to meet Spears before showtime!

Or in Miley's case, she was just saying hello again to her dear friend. After all, she's seen (and loved) the "Piece of Me" Las Vegas show before.