Brandi Glanville's son Mason is recovering after a serious allergic reaction landed him in the ER. Credit: Courtesy Brandi Glanville; Gregg DeGuire/Getty Images

This wasn't on the trip agenda. On Sunday, March 30, Brandi Glanville rushed her son Mason, 10, to the ER, tweeting a photo of the boy in a hospital bed with the caption, "8 hours in the ER this trip to NYC Mason will never forget! 1st trip in an ambulance! All will be fine."

Glanville's rep confirmed to Us Weekly that Mason was doing alright after being treated for anaphylactic shock. 

"He's fine, don't worry," a source told Us. "He had a bad allergic reaction, but he's fine." 

Mason, whose father is Glanville's ex Eddie Cibrian, seems to be recovering nicely. 

"Thanks for your well wishes regarding Mason he is doing a lot better and all will be fine!" Glanville tweeted. 

Cibrian's current wife -- and Glanville's longtime nemesis -- LeAnn Rimes, also tweeted about her stepson's condition, writing, "Got a text from a friend at 4:30am asking if mason was ok. THANK GOD! Mason just called Eddie himself!! It's been a panicked morning not knowing anything and mason being all the way across the US. Relived to know he's ok."

Hours after the episode, Glanville attended Aladdin on Broadway with her son, tweeting, "No sleep and still sooooooo excited!!" After a follower criticized her before going to the show so soon after Mason's ER trip, she responded, "thats all Mason wanted so I made it happen-thats what moms do."