Bert Nievera, a popular balladeer from the Philippines who sang with the Society of Seven showroom act in Waikiki from the mid-1960s to the ’70s, died Monday at Southern Hills Hospital in Las Vegas. He was 81.

His female fans squealed with delight when Nievera, known as Roberto when he was with the SOS, sang with the popular band at the Outrigger Waikiki’s Main Showroom, inspiring his then- young son Martin Nievera to follow in his footsteps to become a Philippine superstar in radio, television, film and concert performances.

“His real name was Bert, but we had three Berts in the group at one time,” said Tony Ruivivar, co-founder of the SOS. “So he became Roberto since we had Bert Sagum (also a co-founder) and Bert Maligmat, who became Little Albert.”

Nievera was widely known for his velvety tones and his Johnny Mathis impressions on such love ballads as “Misty,” “Chances Are” and “The Twelfth of Never.” His other SOS signatures were “This Is My Life” and “Adoro,” the latter featuring a floor-tumbling movement at the height of emotion.

Frannie Kirk, who previously managed the SOS and briefly Nievera, recalled an instance at a lounge at the Sahara resort in Lake Tahoe when Nievera was doing his Mathis take before he joined the SOS.

“He was doing ‘Misty,’ with eyes shut, and the real Johnny Mathis heard this voice and came to see where it was coming from,” Kirk said. “Roberto had his eyes shut and was surprised (to see Mathis) but was excited that he liked the act.”

When he joined the SOS, Kirk said that newbies in the group generally had to learn to play an instrument, so Nievera was assigned the trombonium, a brass instrument featured in the act at one point. “He was bleeding in the lips by the time he learned how to play it,” she said.

Martin Nievera, who regularly saluted his dad’s influences in his own shows, first announced his father’s death via Instagram: “#RobertinParadise I can’t believe you’re gone. Life will never be the same.”

In a later email, he said, “I feel empty and lost; we all do. Dad was such a happy-go-lucky, peace-loving man. He just wanted everyone to get along. And to say Dad loved to sing would be an understatement. He was a master of standing ovations and was the most unserious person you will ever meet.”

Receiving word of Nievera’s decline, Martin and his twin sister, Vicky, flew from Manila to Las Vegas, where they met younger sister Rachel, who had flown in from West Palm Beach, Fla.

“He was a great man, a faithful friend and an amazing father to all his children, yesterday and today,” Martin Nievera said. “Our fondest memories will forever be our life as a family in Hawaii, walking up and down Kalakaua Avenue as if it were the runway to our dreams. Watching him sing every night with the SOS at the Outrigger made me chase my dreams.”

Nievera was born Oct. 17, 1936, in Baguio, and had been living in Las Vegas, where he wed his wife, Carol.

“I’ve lost a dear, dear friend. We started in the business together,” said pianist Kit Samson, a veteran Waikiki performer.

Nievera is additionally survived by two grandchildren. Services are pending.