Rebel Wilson shows off her slimmed-down figure in a black dress in new ad for Facebook Portal

She has impressed fans with her incredible weight loss journey since the start of the year.

And now, Rebel Wilson has showed her slimmed-down figure in a new advertisement for Facebook Portal.

In the video, the 40-year-old actress is first seen entering her kitchen and waving at several families on the video calling device.

‘I’m going to show you guys how to make my famous holiday rolls because tis is the season,’ she said.

The actress then explained: ‘First up you are going to want to knead the dough. Give it some life.’

‘And then you are going to want to talk to the dough like it’s your ex-boyfriend,’ Rebel added.

She then held the dough in her hand and said: ‘Karl I’m not giving you the sweatshirt back and I’ve stretched it so it won’t even fit you.’

After placing the dough onto the table, Rebel glanced at the video device and said: ‘Ok guys you’re not doing it, your rolls are going to be terrible.’

Meanwhile, Rebel has been on a health journey this year, losing at least 18kg (40lbs or 2.8 stone).

According to People magazine, her remarkable transformation is partially down to following the Mayr Method diet plan.

‘It’s an approach that eliminates food intolerances, reduces sugar, encourages eating whole foods slowly, boosts the immune system and reduces inflammation,’ a source said.

Her personal trainer Jono Castano Acero revealed to E! Australia that during a typical week, Rebel does a combination of HIIT workouts, mobility, weights and resistance, and has just one day per week of rest.