In an Instagram post today, Jimmy Kimmel paid tribute to the staff at Children’s Hospital L.A. and Cedars-Sinai, who helped save his now-8 year-old son’s life after he was born with a rare congenital heart defect.

The Watch What Happens Live host is putting in some serious overtime this week between filling in for Clarkson on her daytime talk show today, and joining Jenna Bush Hager on Today with Jenna & Friends Tuesday.