Holly Willoughby could be set to co-host 'I'm A Celebrity... Get Me Out Of Here!'.

Holly Willoughby

Holly Willoughby

The 'This Morning' presenter is being lined up to join Declan Donnelly in the jungle just in case Ant McPartlin decides he wants some time off after he completes rehab.

A source told the Daily Star Sunday: "'I'm a Celeb' is ITV's biggest show of the year so they're keen to get a plan in place should Ant want to continue his down time.

"Holly is the number one choice, she's the nation's favourite and already a huge fan of the show - the perfect Jane of the jungle to Dec's Tarzan!

"Building on-screen chemistry and relationships is what Holly does best, which is perfect for the jungle."

Caroline Flack is reportedly the station's second choice if Holly can't take part, with Scarlett Moffatt and Mark Wright also being considered.

The insider added: "Holly's the perfect cover for Ant. She's wholesome, fun and has the experience needed to pull-off the comedy links expected of the presenters.

"That's something which upcoming stars like Scarlett and Mark don't have yet. It's ITV's blue chip show and there's no way they'd risk handing Ant's role to a wild- card signing."

Meanwhile, it was recently revealed that Ant will be supported by TV bosses if he wants to take a "12 month sabbatical" after he completes two months at a rehab clinic to seek help for his addiction to prescription drugs and alcohol.

A television insider said: "It is all still too early to say for sure what will happen, but all anyone wants is for Ant to get well again. He and Dec are the backbone of the ITV family and ... Ant has the network's complete and utter support.

"Formally, Ant has no work commitments until November and obviously the hope is that he will be completely better by then, and able to fulfil them. But ITV will not rush him in any way, and the feeling is he must take as long as he needs.

"If he wants a 12 month sabbatical, frankly he deserves it. The sense is though that both Ant and Dec love working, and Ant will want to get back down to work before the end of the year."