Backshall is best known for CBBC's wildlife programme Deadly 60 in which he tracks down 60 of the world's deadliest animals.
He made the announcement this morning live on BBC Breakfast.
He said: "My day job filming wildlife in jungles and swamps is nothing like as scary as what is ahead.
"I think Strictly Come Dancing is going to be my wildest challenge by far."
Backshall will be joining EastEnders bad boy Jake Wood, Mark Wright, who shot to fame on reality show The Only Way Is Essex, singers Simon Webbe and Frankie Bridge, former rugby player Thom Evans, presenter Alison Hammond, tennis matriarch Judy Murray, actress Sunetra Sarker and other celebrities still to be revealed.