Jenni, one of the trust's ambassadors, will be joined by her fiance James Midgley for the fifth annual Palace to Palace fundraiser to be held on Sunday, September 26.
She said: "James and I plan to ride Palace to Palace on a tandem bike - I'll be in the driving seat, setting the precedent before we get married. Jokes aside, we're really looking forward to the day and to raising money to help disadvantaged young people through the Prince's Trust."
Other famous names planning to take part include Magic 105.4 presenters Neil Fox and Angie Greaves and presenter Fern Britton.
Approximately 3,000 people are expected to tackle the route, with keen cyclists over the age of 16 being encouraged to sign up for this year's event.
The route stretches from Buckingham Palace, along the River Thames and through three royal parks, with the final part of the ride going through Eton towards the shadows of Windsor Castle.
Cyclists are asked to pay a £30 registration fee and raise at least £45 sponsorship money. Last year's event raised £250,000.
The Prince's Trust was founded in 1976 by the Prince of Wales to support young people and help them access work, education or training.
For more information, visit www.princes-trust.org.uk/palace.