As “Dancing with the Stars” competitors prepare for their third performance Monday night, many stars have taken to Twitter expressing how hard they are working.

Dancing either the Rumba, Waltz, Foxtrot, and Samba this week, stars including Kristin Cavallari and Chaz Bono have said they are experiencing trouble during rehearsals.

Last week Cavallari had a tough start to learning the Samba with her partner, Mark Ballas. She wrote on Twitter, “I had a rough day rehearsing. I started to pick it up at the end but the samba is hard!”

“I’m exhausted!” Wrote Cavallari after rehearsing again Saturday. “Just finished a 5 hour rehearsal that killed me. The samba is definitely hard but I’m starting to have fun with it.”

Cavallari was told by “DWTS” judges that she has great potential, and proves to be a main contender for the mirrorball trophy.

“Going over video for my rumba with @LaceySchwimmer for Monday,” Bono wrote on his Twitter account last week. “It’s challenging to learn a new dance in 5 days, but I’ll be ready.”

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On Saturday, two days before the performance, Bono mentioned his injuries, tweeting, “My knees and ankles are feeling much better. Let’s get ready to Rumba.”

Bono, the only child of Sonny and Cher, underwent a gender transformation last year, changing his name from Chastity to Chaz. His inclusion to the cast of season 13 of “DWTS” was met with much controversy over not only his gender, but his weight.

Rob Kardashian of the reality series “Keeping Up With the Kardashians” posted on Twitter ahead of his performance with partner Cheryl Burke: “Time to rehearse all day! Working on this foxtrot! Next week is Most Memorable Year of Your Life and for a very meaningful song! Can’t wait!”

“DWTS” co-host, Brooke Burke, urged viewers to tune into tonight’s show, posting on Twitter Sunday: “I just left #DWTS, seriously I was crying watching the packages. Don’t miss tomorrow night’s very personal show! Wow.”

“DWTS” will air tonight on ABC at 8 p.m. EST. Tomorrow evening, the third couple to be eliminated will be announced on the results show.