Don't get Carried away!

After winning best country album at the 40th Annual American Music Awards on Sunday, Carrie Underwood and husband Mike Fisher celebrated at Koi Los Angeles.

"They looked happier than ever. Carrie seemed overjoyed and excited throughout the evening and every time her husband made a toast," an onlooker tells PEOPLE. "Her demeanor made it obvious to everyone – even those who didn't catch the show – that she had taken home an important award."

Underwood and Fisher weren't the only two enjoying Koi after the AMAs. On the back patio, Gloria Estefan, joined by her husband and several friends snacked on signature sushi rolls and crispy rice.

Still dressed up from the awards, the group "laughed and enjoyed themselves all night," the source adds. – Carlos Greer

Kyle Richards got her fishy fill when she recently stopped by Koi restaurant in West Hollywood.

Coming out to celebrate the birthday and launch of fellow Bravo TV personality Patti Stanger's new site PattiKnows.com, Richards was offered an array of sushi options, along with pan-seared dumplings and steak skewers, once she mentioned she was "starving."

"Kyle came with [Flipping Out's] Jenni Pulos," an onlooker tells PEOPLE. "Kyle didn't walk the pink carpet at the event. She said her husband would be joining her later, but she didn't want to wait for him, so she and Jenni were immediately seated at a V.I.P. booth. Her husband never ended up coming."

As the ladies sipped on white wine, Richards's fellow Real Housewives of Beverly Hills costars Lisa Vanderpump and her hubby Ken Todd joined the gals in their booth.

"They all continued to eat and drink together," the source says. "Patti came over at one point and gave big hugs to her guests while they showered her with birthday wishes. Kyle and her crew stayed for about an hour and a half. They seemed to be enjoying the party, but definitely kept to themselves."
– Dahvi Shira

Kelly Clarkson and Miranda Lambert were joined by friends for dinner at Koi New York. According to a source, the ladies "seemed to be having a lot of fun and laughing" during their meal of crispy rice and spicy tuna – which is Kelly's favorite dish. Clarkson arrived first, with her two friends, then Lambert joined them with two pals of her own. – Lesley Messer

Ryan Phillippe stepped out for a guys' night out at Koi in Los Angeles, where the actor shared a late dinner with pals. Despite an attempt at anonymity thanks to a hoodie, the actor ended up nabbing a prime table outside on the restaurant's front patio as he enjoyed a laughter-filled meal.

Family was the focus Thursday night for Ashton Kutcher and Demi Moore, who joined Bruce Willis and his wife, Emma Heming, at daughter Rumer Willis's debut performance in Love, Loss and What I Wore in New York City. "They all greeted each other with hugs and kisses," a witness tells PEOPLE. "They definitely looked like one big, happy extended family." Kutcher and Moore also popped into Koi New York that night, dining with the budding actress and a few pals.

Eva Longoria and rumored beau Eduardo Cruz stopped into Koi Los Angeles for a flourless molten chocolate volcano cake. But the hottest thing at the table was Cruz's obvious affection for the Desperate Housewives star. He couldn't keep his eyes off her, and the two got cozy as they enjoyed their chocolate treat on the back patio.

Joe Jonas, enjoying a romantic dinner with girlfriend Ashley Greene at Koi in L.A. The couple, who kissed and held hands from the minute they walked in, were in a "relaxed mood," an onlooker says. The two ordered a round of drinks – sake for him, a pumpkin pie martini for her – with their dinner. What else was on the menu? Champagne – for fellow diners Lady Antebellum since Jonas, a big fan of the band, sent the group a bottle of Dom Pérignon.