Must-See Celeb Sightings: Dec. 18-31, 2019

Denim in the water! The bikini-clad model wrapped up 2019 on the beach in St. Barths, France, on Dec. 31.

The mom of three got some end-of-the-year shopping done in Aspen, Colorado, on Dec. 31.

The model rocked an all-black look as she walked through the snow to her New Year's Eve festivities in Aspen, Colorado, on Dec. 31.

Rocking an electric blue top paired with a black-and-white checkerboard skirt, the "New Rules" songstress slayed on stage while performing live in Hollywood on Dec. 31 as part of ABC's Dick Clark's New Year's Rockin' Eve With Ryan Seacrest 2020.

Posty shined bright in his metallic pink, star-adorned suit during the same NYE celebration.

The multihyphenate flashed a big grin while hosting his annual New Year's Eve television special in New York City's Times Square on Dec. 31.

Also in Times Square with Ryan Seacrest? A latex-clad Ciara! 

The English singer became part of a Vampire Diaries reunion as these lovely ladies celebrated New Year's Eve together at the grand opening of the Bellagio Resort & Casino’s new supper club, The Mayfair, in Las Vegas.

Sparkle and shine! The actor struck a pose ahead of celebrating New Year's Eve in New Orleans.

The rapper dropped it like it's hot during his New Year's Eve 2019 set at E11EVEN Miami in 

The party didn't stop after the ball dropped! The Watch What Happens Live With Andy Cohen host showed up to celebrate the New Year at the Freixenet 2020 Celebration held at TAO Uptown in New York City.

Risky Business vibes! The 45-year-old actor rang in 2020 in a private cabana at the annual NYE WET poolside party at W South Beach in Miami on Dec. 31.

The lovebirds walked arm in arm through Mendes' hometown of Toronto on Dec. 30.

Snowboard star! The Carnival Row actor hit the slopes in Aspen, Colorado, on Dec. 30.

The L.A.'s Finest star enjoyed a girls night out with Olivia Munn and Kelly Rowland in Beverly Hills on Dec. 30.

The "Truth Hurts" rapper gave one of her last performances of 2019 at Marquee Nightclub in Las Vegas, Nevada, on Dec. 30.

The TV personality and the Pretty Little Liars alum bundled up against the cold during a press junket ahead of their upcoming Dick Clark's New Year's Rockin' Eve With Ryan Seacrest 2020 special, posing in front of the iconic Times Square ball in New York City on Dec. 30.

The former Dancing With the Stars pro was all smiles as she walked through the parking lot of a dance studio in Los Angeles on Dec. 28.

The "Blurred Lines" crooner and son Julian hung out with the Peanuts gang at Knott's Berry Farm in Buena Park, California, on Dec. 27.

The singer and friends received a special preview of The Mayfair Supper Club at the Bellagio in Las Vegas on Dec. 27. Gaga looked radiant in a long sparkly gown with matching headband, diamond earrings and black heels as she took in the experience.

The pair was photographed walking hand-in-hand in New York City's West Village on Dec. 27.

The actor and comedian struck a pose together while watching the Los Angeles Lakers take on the Los Angeles Clippers at the Staples Center on Dec. 25.

The Keeping Up With the Kardashians star was outfitted in dusty hues as she got some last-minute Christmas Eve shopping done in Woodland Hills, California.

The actor pals enjoyed a Christmas Eve walk through New York City.

Mimi enjoyed some shopping followed by dinner at the French Alpine Bistro in Aspen, Colorado, with boyfriend Bryan Tanaka (not pictured) on Dec. 24. Carey wore a black jacket, ski pants and a red scarf and black boots, both by Louis Vuitton, for the outing.

Festive for a Miami Christmas! The Hustlers star showed off her abs in a bold red sports bra and matching leggings as she hit the gym on Dec. 24.

The couple looked so in love as they smiled and walked hand in hand in the Palm Beach area of Sydney, Australia, on Christmas Eve.

The American Horror Story actress got some last-minute Christmas Eve errand done in Los Angeles' Larchmont Village on Dec. 24.

Those boots were made for walking! The Voice coach rocked a colorful coat and white cowboy boots while shopping in Beverly Hills on Dec. 23.

Doin' good for the holidays! The America's Got Talent host brought son Golden along to the "Christmas Celebration on Skid Row" at the Los Angeles Mission on Dec. 23.

There was plenty of hilarity courtside at the Washington Wizards vs. New York Knicks game at NYC's Madison Square Garden on Dec. 23, where Schumer and her husband, Chris Fischer, were sitting alongside the rapper and the Patriot Act With Hasan Minhaj host.

The Aussie singer and his actor pal chatted away on the streets of New York City's SoHo neighborhood on Dec. 23.

The cute couple looked ecstatic as Urban picked up his wife at the airport in Sydney on Dec. 22 so they could spend Christmas together in their native Australia.

Kimye looked sharp upon arrival at the Jane Hotel in New York City on Dec. 22. The duo was there for the official after-party of the rapper's opera, Mary, which opened at Lincoln Center.

The exes were hit the slopes together while vacationing in Aspen, Colorado, on Dec. 23.

The Brazilian model and her boyfriend, Nicolo Oddi, weren't afraid of a little PDA as they walked around Los Angeles on Dec. 23.

The JoBros wowed fans during their set at Y100's Jingle Ball 2019, presented by Capital One, at the BB&T Center in Sunrise, Florida, on Dec. 22. The show marked the final stop of this year's national iHeartRadio Jingle Ball Tour.

Coordinating in plaid and leather, the lovebirds held hands and flashed big grins as they exited the Gucci store in Aspen, Colorado, on Dec. 22.

The English singer rocked a red bikini, beige headscarf and black sunglasses as she hit the beach during her Saint Barts vacation with her parents and friends on Dec. 21.

The Keeping Up With the Kardashians star donned an all-leather look under a silver puffy jacket as she exited a limo in New York City on Dec. 21.

The Sky Is Pink star looked chic in a monochrome ensemble as she headed out in New York City to do some Christmas shopping on Dec. 20.

Here's looking at you, too! Timberlake pointed to photogs who spotted him leaving a business meeting in Beverly Hills in an upbeat mood on Dec. 20.

Multi-tasking mama! The "All I Want for Christmas Is You" singer flashed a grin while holding boyfriend Bryan Tanaka's hand and taking a phone call as they hit the streets of New York City on Dec. 20.

The "Don't Start Now" singer was all smiles as she walked arm in arm with her beau through New York City's SoHo neighborhood on Dec. 20.

The Bombshell babe waved to photogs before heading into the L.A. set of Jimmy Kimmel Live! on Dec. 19.

The newly crowned Miss America 2020 was joined by the Queer Eye guy, the Superstore star and the singer for the Miss America Post Press Conference at Mohegan Sun in Uncasville, Connecticut, on Dec. 19.

The engaged duo was sitting pretty courtside as the Los Angeles Clippers took on the Houston Rockets at L.A.'s Staples Center on Dec. 19.

The CATS star looked sharp in his all-black duds while out in New York City on Dec. 19.

The blonde beauty gave a wave before heading into Nine Zero One Salon in West Hollywood on Dec. 19.

Double the fun! The model flashed two peace signs while taking in the view at the MDL Beast Festival in Riyadh, Saudi Arabia, on Dec. 19.

The youngest JoBro bundled up in a fringe-adorned puffy jacket during an afternoon shopping trip in New York City on Dec. 19.

Blue crew! The co-stars looked like royalty at the European premiere of Star Wars: The Rise of Skywalker in London on Dec. 18.

The "Señorita" singer made the crowd in Monterrey, Mexico, swoon as he crooned during his Dec. 18 concert.

Joe, Nick and Kevin Jonas looked sharp ahead of their performance at 103.5 KISS FM's Jingle Ball 2019 in Chicago on Dec. 18.

Sweatpants and shopping! The comfy-looking "Lose You to Love You" singer walked back to her car with two Urban Outfitters bags after a spending spree in Los Angeles on Dec. 18.

The Marvelous Mrs. Maisel star was bundled up in black attire during a blustery New York City morning on Dec. 18.

The English singer lit up fans' lives when he posed with them for pics -- while rocking a T-shirt with his name on it!) -- as he left BBC Radio One in London on Dec. 18.

The Big Bang Theory beauty got giggly while filming a scene for The Flight Attendant in New York City on Dec. 18.

The athleisure-clad model was on a silver streak in New York City on Dec. 18.

Outfitted in shades of olive green, the Just Mercy star stepped out in New York City on Dec. 18.

The Queer Eye star joined the Olympian to celebrate Rippon's Ketel One Family Made Vodka- and Portal A-hosted "Break the Ice" wrap party at the Hills Penthouse in West Hollywood on Dec. 18.

Despite being in Miami, the singer donned a furry, all-black ensemble during a CATS press day on Dec. 18.