The TV titan became a co-owner of the diet company in October (15), after buying 10 per cent of the firm, while she also agreed to front its new advertising campaign and document her own New Year slim down.

Oprah, who has long struggled with weight issues, unveiled her first commercial over Christmas, using flashback footage of her past dieting efforts to urge fans to join her in her new challenge, stating, "If not now, when?"

She ends the ad by adding, "Are you ready? Let's do this together."

Tyler has since confessed he doubted Oprah's latest business venture at first, because he didn't think she needed to front the brand and face her figure problems in public.

"I didn't get that WeightWatchers thing at all, like, 'Why are you doing this? What are you doing?'," he explained to U.S. breakfast show Good Morning America. "But talking to her about it, I get it. The passion of just who she is and where she's come from and all that she's been through, she has something to say and I think every person that joins her is gonna really go on that journey and get there. And I'mma (sic) say right now, she's doing awesome."

Tyler revealed his own efforts to get fit in November (15), when he showed off his toned physique and admitted he was 18 pounds (8.1 kilograms) away from his target weight.

The Gone Girl star admits his goal is now a little further away after indulging over Christmas, but he's confident he will succeed.

"I'm 24 pounds away now, I couldn't hold out, but I'll get there...!," he laughs. "And if I can't get these 24 pounds (off), I'll be like (calling Oprah), 'Hey, what do I do to get on this WeightWatchers thing with you?'"