This article originally appeared on People.com.

Jimmy Kimmels baby boy?William John “Billy” is a fighter!

ABC announced on Monday in a statement the 7-month-old “had a scheduled and successful heart surgery today.” The network also says Kimmel is “with his family” and will have celebrity guests filling out as host of Jimmy Kimmel Live! for the week.

In Kimmel’s place, Chris Pratt will kick things off Monday, and he’ll be followed by Tracee Ellis Ross, Neil Patrick Harris and Melissa McCarthy. Guests include Margot Robbie, Chris Stapleton, Mary J. Blige, Amanda de Cadenet, Miguel, Vanessa Kirby, Jules Sylvester, Octavia Spencer, Dave Franco and Hanson.

Originally, Billy’s surgery was scheduled at the end of October but needed to be postponed “due towards the common cold,” the network said in a statement at that time.

In April, Kimmel and his wife?Molly McNearney?welcomed William John “Billy” Kimmel and announced that at 3-days-old, Billy underwent the surgery at?Children’s Hospital La?due to his condition,?the?tetralogy of Fallot with pulmonary atresia.

“Basically, the pulmonary valve was completely blocked and he includes a hole within the wall between the left and right sides of his heart,” Kimmel previously explained inside a?tearful monologue?in May, adding that despite the successful open heart surgery, Billy may have another operation between 3 and 6-months-old.

Kimmel and McNearney also share a 3-year-old daughter, Jane. The host has two older kids C Kevin and Katie C from the previous relationship.

Jimmy?Kimmel?Live?airs?weeknights (11:35 p.m. ET).