The former Hollywood couple's second daughter sang several tracks with her group Gus + Scout at the Mercury Lounge in the Big Apple, while dad Bruce and sisters Tallulah and Rumer cheered from the crowd.
Moore was not present at the gig.
Scout swigged on beer throughout her set, but she no longer had to fear being caught out by America's underage drinking laws again as she turned 21 in July (12).
She was ordered to complete two days of community service in June (12) after handing over a fake identity card to cops who had allegedly found her drinking beer in New York's Union Square.
The 23 year old, who has appeared in such TV shows as 90210 and The Secret Life of the American Teenager, enjoyed a date with The Hard Times of RJ Berger actor at Hollywood hotspot Bagatelle LA last week (03Jul12).
A source tells the New York Post, "She sipped on bourbon, while Jason draped his arm around her the whole evening. The two were holding hands, flirting and canoodling."
The couple later continued its evening at nearby Sayers Club, where Willis performed a few songs.
The actress has been previously linked to High School Musical hunk Zac Efron as well as Glee stars Mark Salling and Chord Overstreet.
The House Bunny actress, 23, has been trying to locate her beloved Indy Blue for the past few days and has been putting up numerous 'Lost Dog' posters around her neighbourhood, to no avail.
Rumer Willis adopted the Terrier-Beagle mix from a shelter two months ago, reports TMZ.com.
Demi Moore and new dad Bruce Willis reunited on Thursday (07Jun12) to watch their youngest daughter graduate high school. The former couple was joined by daughters Rumer, 23, and Scout, 20, who kicked off last week (beg04Jun12) with an underage drinking arrest in New York.
The couple welcomed the tot to its family last month (Apr11), and Heming-Willis is now tirelessly doting on the newborn.
But her parenting skills were tested to the limit this week (beg14May12) when Hollywood hardman Willis had to spend a day away from the family and his wife was left to tend to their daughter solo.
Taking to Twitter.com, she writes, "I have a whole new respect for my Mom & other single parents trueheros (sic) I only had 24hrs alone with Mabel and thank goodness Daddy is home."
The baby is the couple's first but Heming-Willis is stepmother to her husband's grown-up girls - 23-year-old Rumer, 20-year-old Scout and 18-year-old Tallulah - from his marriage to Demi Moore.
Bruce Willis may be an incredible actor, but he is also an adoring father. Thanks to a photo that his wife Emma Heming, 35, posted on Twitter Thursday, fans get to see the actor's softer side as he cuddles with his newborn daughter, Mabel Ray.
“A beautiful day in Budapest with the loves of my life. Daddy and Mabel cracking each other up,” Heming captioned the precious shot. Who knew John McClane could be so sweet? Willis may just have a sixth sense when it comes to parenting. But seriously, this photo is just adorable — and it's the first time the world has ever really gotten an up-close look at baby Mabel. Isn't she a cutie?
The couple welcomed their little bundle of joy on April 1. Mabel is their first child together, but the 57-year-old actor also shares three daughters — Rumer, 23, Scout, 20, and Tallulah, 18 — with ex-wife, Demi Moore.
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The Hollywood action man, who has three grown-up girls from his marriage to Demi Moore, welcomed a baby daughter called Mabel Ray with his second wife Emma Heming.
A spokesperson for the Die Hard star tells People.com the new parents "are overjoyed about the newest member of their family," adding, "Both mother and baby are healthy and doing beautifully."
Heming, 33, gave birth to the baby in Los Angeles and the tot weighed in at nine pounds, one ounce (4.1 kilograms).
Willis, 57, who married Heming in 2009, is also dad to 23-year-old Rumer, 20-year-old Scout and 18-year-old Tallulah, with his ex-wife Moore.
Bruce Willis is a daddy again at 57. The G.I. Joe: Retaliation star and his designer wife Emma Heming, 33, welcomed a baby girl named Mabel Ray on April 1 in Los Angeles, Calif.
While little Mabel Ray is the couple's first child, Willis has three older daughters — Rumer, 23, Scout, 20 and Tallulah, 18 — from his previous marriage to Demi Moore. That's a pretty big age gap between his older girls and the new baby.
But Willis and Heming couldn't be happier about their new addition, even if she weighed in at a surprising 9 lbs., 1 oz. "They are overjoyed about the newest member of their family," Willis' rep says. "Both mother and baby are healthy and doing beautifully."
Congrats to the proud new parents!
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Kutcher split from his wife Demi Moore, who is Rumer's mum, last November (11) after six years of marriage, but that doesn't mean the actor has cut all ties with her three children with ex-husband Bruce Willis.
The star was spotted at The Sayers Club on Monday night checking out the singer's performance, according to TMZ.com.
Rumer has been in need of strong moral support as of late - her actress mum Moore, who was not present at the show, was hospitalised in January (12) after she was found semi-conscious at her Hollywood home. The Ghost beauty later spent two days at a medical facility for exhaustion and stress, and she reportedly completed more treatment in Utah last week (begs27Feb12) before heading off for a short vacation in Turks and Caicos.
Moore returned home to California on Sunday (04Mar12).