Amy Schumer's son Gene was hospitalised with RSV (Respiratory syncytial virus) amid her 'Saturday Night Live' rehearsals.

The comedienne admitted last week was the "hardest" of her life as her three-old boy - whom she has with husband Chris Fischer - was battling the viral infection as she performed hosting duties on the late-night sketch show.

Alongside some backstage snapshots of her time hosting 'SNL', she wrote on Instagram: "This was the hardest week of my life.

"I missed Thursday rehearsals when my son was rushed to the ER and admitted for RSV. Shout out to all the parents going through this right now."

Thanking the crew for working around her visit to the hospital to be with her little boy, she said: "I got to be with him the whole day at the hospital and the beautiful humans at @nbcsnl couldn't have been more supportive."

The 'Trainwreck' star reassured her followers that Gene is "home and better" as she continued to praise the cast and writers who went out of their way to ensure everything run smoothly, and the doctors and nurses who looked after the youngster.

She went on: "My son is home and better. The reason this show is so fun to do isn’t actually the performance or the show itself. It’s getting to spend time with the people there. The cast and the writers of course but the people who are behind the scenes making it run smooth are my favorite. The crew! Donna. Jerry. Jodi. Genna. Tom Wally and on and on. Lorne has assembled the most talented people with the kindest hearts. Thank you everyone there and to the doctors and nurses who helped us."