Jenna Johnson is used to competing against family on Dancing With the Stars, but she misses having sister-in-law Peta Murgatroyd in the ballroom. "She's incredible," Johnson, 31, told Us Weekly exclusively after the season 34 cast was officially announced on Wednesday, September 3. "But she's killing it. ... I'm so, so happy and proud of her." Johnson also acknowledged that Murgatroyd, 39, has a full house at home with husband and fellow former DWTS pro Maks Chmerkovskiy. (The couple, who tied the knot in 2017, share sons Shai, 8, Rio, 2, and Milan, 13 months.