Lisa Vanderpump and Bethenny Frankel were noticeably missing from Andy Cohen's extravagant baby shower on Saturday

Lisa Vanderpump had a business reason for skipping Andy Cohen‘s star-studded baby shower.

The Real Housewives of Beverly Hills star was in Las Vegas for business over the weekend. Vanderpump shared a photo of herself in Sin City, explaining that she was working on her upcoming Vanderpump Cocktail Garden.

“Wow a creative day in Vegas…You have to check out, my friend and partner at world market @nickalain as we create our Vegas cocktail garden. His showroom is phenomenal,” she wrote.

On Saturday, Vanderpump was noticeably missing from Cohen’s extravagant baby shower, attended by nearly 50 Real Housewives stars. Of course, there’s been some behind-the-scenes drama on Beverly Hills upcoming season as the restauranteur chose not to film with her costars. (“Lisa doesn’t want to be around the women as a group, so she’s getting less filming time. But nobody has quit. She’s definitely still on the show,” a source told PEOPLE in October 2018.)

The Real Housewives of New York City stars Bethenny Frankel and Luann de Lesseps didn’t attend the bath, either. The Countess was busy with her cabaret show, and a friend of Frankel’s tells PEOPLE that the Skinnygirl mogul had a speaking engagement Saturday afternoon at the Nazarian Institute that “was booked months in advance.”

“Everybody knew she was not going to be able to attend,” the friend explains. “The speaking engagement was booked way before Andy’s party and it was at the same time. All the Housewives knew she was not going to be at the party because of this.”

From left: Lisa Vanderpump, Andy Cohen and Bethenny Frankel
| Credit: Charles Sykes/Bravo (3)

Original Housewives Kyle Richards (Real Housewives of Beverly Hills), Vicki Gunvalson (Real Housewives of Orange County), Ramona Singer (Real Housewives of New York City), NeNe Leakes (Real Housewives of Atlanta), and Teresa Giudice (Real Housewives of New Jersey) organized and hosted the event at The Palm Beverly Hills in Los Angeles.

“We kept the list to mainly Housewives to simplify things,” Richards told PEOPLE. “Most men can barely handle one wife and Andy has a lot of wives to deal with!”

Guests included LeeAnne Locken (Real Housewives of Dallas), Gizelle Bryant (Real Housewives of Potomac), Dorinda Medley (RHONY), Sonja Morgan (RHONY), Shannon Beador (RHOC), Tamra Judge (RHOC), Erika Girardi (RHOBH), Margaret Josephs (RHONJ), Dolores Catania (RHONJ), Lisa Rinna (RHOBH), Jackie Goldschneider (RHONJ), Brandi Redmond (RHOD), Stephanie Hollman (RHOD), Candiace Dillard (RHOP), Ashley Darby (RHOP), Karen Huger (RHOP), Gina Kirschenheiter (RHOC), Emily Simpson (RHOC), Kameron Westcott (RHOD), Teddi Mellencamp Arroyave (RHOBH), Jennifer Aydin (RHONJ), Danielle Staub (RHONJ), Phaedra Parks (RHOA), Cynthia Bailey (RHOA), Robyn Dixon (RHOP), Denise Richards (RHOBH) and Eva Marcille (RHOA).

“I’m speechless. Every Housewife, featuring @JohnMayer,” Cohen, 50, wrote of a group shot of the Housewives, plus the singer-songwriter.

Many of Cohen’s guests shared Instagram Stories capturing the activities at the baby shower, which included an artist drawing caricatures. Cohen appeared to be recording an episode of his SiriusXM show from the event, according to video shared by Richards.

Cohen has been in Los Angeles since Jan. 14, having moved WWHL out west for a quick babymoon before his son’s February arrival. The show planned to air episodes from there for three weeks.

“Moving the Clubhouse to L.A. is a win all the way around,” Cohen told PEOPLE in a statement earlier this month. “There will be great guests, great energy and I can make a 9 p.m. dinner reservation after we get off the air!”

Since making his announcement, Cohen has been showered with love from his fellow Real Housewives stars. Their supportive sentiments were carried over by best friends, like Sarah Jessica Parker — who spoke to PEOPLE exclusively.

I am overcome with joy and join Andy’s friends and family as we anticipate the safe arrival of the already much-loved baby Cohen,” Parker, 53, told PEOPLE. “Andy will be a wonderful father and has been waiting forever to be called Papa.”

“I can’t wait to meet and know his child and offer any help or guidance I can offer the new daddy,” she added. “This has been a hard secret to keep and I was so thrilled to hear him share his very happy news last night. Now we are just counting the days.”

Lincoln Center's American Songbook Gala - Arrivals
Andy Cohen
| Credit: Mike Coppola/Getty Images

Of course, the father-to-be is even more excited.