Ciara, Boyz II Men, Charlie Wilson and Ella Mai will be joining Mars on select dates for the remainder of the tour which continues throughout North America until Nov. 8 where it will conclude with three shows at Aloha Stadium in Honolulu.
Mars made the announcement on Instagram Tuesday, introducing each special guest one-by-one in a video where he briefly performed some of their most well-known songs.
Cardi B exited the 24K Magic tour in July, following the birth of her daughter Kulture Kiari whom she shares with husband Offset of Migos fame.
"As of today I've decided I won't be joining Bruno on tour this Fall. I thought that after giving birth to my daughter that 6 weeks would be enough time for me to recover mentally and physically. I also thought that I'd be able to bring her with me on tour, but I think I underestimated this whole mommy thing," she said in a statement at the time.
Mars first kicked off the 24K Magic tour in March 2017 in support of his third studio album of the same name. The project won Best Album at the 2018 Grammy Awards with Mars also taking home awards for Song of the Year, Best R&B Performance and Best R&B Album.