Honey Ross was bitten by an adder while on a day trip to Poole, Dorset, with Film 99 presenter Ross, her brother Harvey and older sister Betty Kitten.
Doctors at Poole General Hospital treated the youngster after she was admitted yesterday and she was kept in overnight on a paediatric ward.
"She is in a comfortable condition and will probably be released this afternoon," said a hospital spokeswoman.
"Adder bites are not usually fatal but they can be if left untreated.
"We have about two or three cases annually and it is more common at this time of year because the snakes are dozy after coming out of hibernation."
Adders, the only poisonous snakes in Britain, can grow to two feet in length and have a distinctive V-shaped mark on their heads.