A host of stars are helping the charity celebrate its 25th anniversary

A host of celebrities are lending their support to this year’s Comic Relief to help raise money for good causes.

In honour of Red Nose Day two of the UK’s biggest comedy names, Dawn French and Jennifer Saunders, will be popping up on BBC Radio 2 on Friday.

The big night of the TV relief effort will see a star-studded line-up of comedians perform as the charity celebrates its 25th anniversary.

The last Red Nose Day, in 2011, raised a record breaking £74.3m.

French and Saunders have been preparing for their stint on Radio 2 on Friday by familiarising themselves with the station’s schedule and presenters.

The duo plan to cause “chaos and confusion” on the station and have fun with listeners’ favourite features.

At lunchtime, for example, they will give presenter Jeremy Vine a lesson in how to deal with the day’s important issues.

French and Saunders will take over the airwaves on Radio 2 on Friday

So far in the 2013 relief effort, there have been both dangerous and cringe-worthy Red Nose moments.

Celebrities including Dara O Briain, Melanie C, Jack Dee and Greg James took on the five-day Hell and High Water challenge, travelling down the 100km Zambezi River to raise £1m for children in Zambia.

The group will be live in the studio on Friday night to tell viewers about their experiences in Africa.

Comedienne Miranda Hart has been doing her bit for charity by completing a Mad March challenge each day this week in different cities across England.

Hart will also take part in Friday night’s live telecast and treat viewers to a comedy special of her popular drama Call the Midwife.

Miranda will be joined by Jessica Raine, Pam Ferris, Jenny Agutter and the other midwives as they struggle to get to grips with an unusual birth.

Meal worms and maggots

On Thursday, model Kate Moss was among a host of celebrities who helped out with the fundraising efforts on Nick Grimshaw’s breakfast show on Radio 1.

Other guests on the show, during which Grimshaw was submerged in a bath of meal worms and maggots to raise money, included comedian David Walliams, presenter Claudia Winkleman and pop group Little Mix.

Peter Kay has taken on what he calls the “toughest challenge ever undertaken for Red Nose Day” – forcing himself to sit down for practically a whole week.

Miranda’s Mad March saw Hart (r) complete a series of challenges in different cities across England

Kay’s challenge will be shown on Friday night, with the comedian hoping to make a triumphant arrival at BBC Television Centre.

Highlights will also be shown from Mark Watson’s recent 25-hour stand-up gig and Graham Norton’s Big Chat talk show marathon.

Other items on the telethon show include an appearance by James Corden, who will reprise his role as the loveable Smithy from Gavin and Stacey.

It will also see US funny man Will Ferrell appear as San Diego “anchorman” Ron Burgundy in a one-off sketch recorded especially for Red Nose Day.

There will also be a performance from boy band One Direction, who have recorded this year’s official Red Nose Day single – a mash-up of Blondie’s One Way or Another and Teenage Kicks by The Undertones.

Meanwhile, singer Jessie J will make good on a long-standing pledge to shave her head for charity.

Comic Relief – Funny for Money begins on BBC One at 19:00.