Karl Stefanovic’s Today Show co-stars surprise him on-air with a hilarious birthday cake

He recently revealed he lost an impressive eight kilos before vowing to shed another seven.

But on Wednesday, Today Show host Karl Stefanovic’s diet appeared to go out the window as his colleagues surprised him with a hilarious cake to celebrate his 46th birthday.

Dressed in a stripey shirt, eye mask and cape, like the Hamburlgar who featured in ads for McDonald’s in the 80s, entertainment reporter Brooke Boney presented Karl with a cake shaped like a massive cheeseburger.

Surprise! On Wednesday, Karl Stefanovic’s (left)  Today Show co-stars surprised him on-air with a hilarious cheeseburger cake to celebrate his 46th birthday (also pictured is Allison Langdon) 

‘Wow! That is so cool. A cheeseburger birthday cake,’ the veteran journalist exclaimed in delight.

His co-host Allison Langdon then explained what had inspired the rather unique design.

‘It combines your two great loves. Cake and burgers,’ she said, breaking into a giggle.

Inspiration: His co-host Allison then explained what had inspired the rather unique design. 'It combines your two great loves. Cake and burgers,' she said, breaking into a giggle

Inspiration: His co-host Allison then explained what had inspired the rather unique design. ‘It combines your two great loves. Cake and burgers,’ she said, breaking into a giggle

Flashback: Dressed in a stripey shirt, eye mask and cape, like the Hamburlgar who featured in ads for McDonald's in the 80s, entertainment reporter Brooke Boney (pictured) presented Karl with his cake

Flashback: Dressed in a stripey shirt, eye mask and cape, like the Hamburlgar who featured in ads for McDonald’s in the 80s, entertainment reporter Brooke Boney (pictured) presented Karl with his cake 

Last week, Karl unveiled his weight loss results after he promised to lose 10 kilograms in 10 weeks while interviewing obesity expert Dr Nick Fuller back in May.

The father-of-four proudly revealed he’d weighed himself at home that morning and had shed an impressive eight kilos.

The Channel Nine star admitted it had been tough finding the time to exercise, but said he was feeling ‘great’.

Weight loss challenge: Last week,  Karl  (centre) proudly revealed he'd weighed himself at home that morning and had shed an impressive eight kilos

Weight loss challenge: Last week,  Karl  (centre) proudly revealed he’d weighed himself at home that morning and had shed an impressive eight kilos

‘In the last couple of weeks it’s been difficult with the baby and all that sort of stuff,’ he said, referring to his youngest daughter, Harper May.

‘It is life getting in the way of it a little bit, but it’s been a fantastic program,’ he added, thanking Dr Fuller, who had supported him throughout his journey.

‘It’s been toughest to find the time to exercise.’

Challenges: The Channel Nine star, who recently became a father for the fourth time, admitted it had been tough finding the time to exercise but said he was feeling 'great'. 'In the last couple of weeks it's been difficult with the baby and all that sort of stuff,' he said, referring to his youngest daughter, Harper May. Karl's wife, Jasmine Yarbrough, is pictured here with Harper

Challenges: The Channel Nine star, who recently became a father for the fourth time, admitted it had been tough finding the time to exercise but said he was feeling ‘great’. ‘In the last couple of weeks it’s been difficult with the baby and all that sort of stuff,’ he said, referring to his youngest daughter, Harper May. Karl’s wife, Jasmine Yarbrough, is pictured here with Harper

Dr Fuller said: ‘It’s been a fun journey with you, but it’s just the start… We will get you to that 90 kilos and keep you there.’

Karl revealed that his program, which included a lighter evening meal, had helped him get to sleep much quicker and left him feeling more refreshed in the morning.

The father of four acknowledged he did have difficulty about halfway through the program, and found that having a cheat day on Friday was helpful.

Exercise: Karl said the hardest part of the program was finding time to exercise. Pictured here with co-host Allison Langdon and The Biggest Loser's Steve 'Commando' Willis

Exercise: Karl said the hardest part of the program was finding time to exercise. Pictured here with co-host Allison Langdon and The Biggest Loser’s Steve ‘Commando’ Willis

 ‘What really worked for me was being good from Sunday to Friday and then having a bit of a cheat meal on Friday – as long as that doesn’t then bleed into Saturday and Sunday,’ he said.

Karl’s always-supportive co-host Allison Langdon praised him for his efforts.

‘I’m very, very proud of you for the last 10 weeks. You’ve worked really hard on this,’ the 41-year-old said.

Support:  Karl's always-supportive co-host Allison Langdon (left) praised him for his efforts. 'I'm very, very proud of you for the last 10 weeks. You've worked really hard on this,' the 41-year-old said. Karl and Allison are pictured with weight loss expert Dr Nick Fuller (right)

Support:  Karl’s always-supportive co-host Allison Langdon (left) praised him for his efforts. ‘I’m very, very proud of you for the last 10 weeks. You’ve worked really hard on this,’ the 41-year-old said. Karl and Allison are pictured with weight loss expert Dr Nick Fuller (right)

‘You fell off once or twice, but I think what’s important is you stuck to this diet and the exercise regime,’ she added.

After vowing to lose weight in May, Karl admitted he was embarrassed before his first weigh-in to have the number revealed on air.

‘It is pretty embarrassing, and I have to admit that, to go and say, “Alright, I’m going to weigh myself on national TV”,’ he said.

Karl’s weight at the time he started the program was 105kg.

On Tuesday, he confirmed he was down to 97kg, and had a goal weight of 90 kilos.

Not going back! After vowing to lose weight in May, Karl said he was embarrassed before his first weigh-in to have his number revealed on air: 105 kg. He has since dropped down to 97kg

Not going back! After vowing to lose weight in May, Karl said he was embarrassed before his first weigh-in to have his number revealed on air: 105 kg. He has since dropped down to 97kg