Fijian-born Speight has had to endure a long wait to become eligible for the Wallabies, but will finally pull on the Australian jersey against the Barbarians at Twickenham early Sunday morning.

Speight spent a lot of the off-season in training with Pocock, trying to overcome a hamstrong injury, and Pocock was blown away by his athleticism.

"He is one of the most impressive rugby players that I've ever played alongside, he's outstanding," Pocock said.

"Just his ability in attack, and also he's got a lot more to his game - his breakdown is very good, defensively he's good.

"I think it's hugely exciting for the Wallabies to have him available for selection and I'd love to see that 'fro in a gold jersey running down the sideline.

"I'd hate to defend him, I'd have nightmares if I had to defend that bloke one-on-one. Those poor wingers."

Roff felt the European teams wouldn't know much about Speight and he could catch them off their guard as the Wallabies look to put a disastrous month off the field behind them.

"I think he's going to set things alight and provide a spark that will be well worth watching," Roff said.

"He was just a standout, world-class, in Super Rugby this year and I can't wait to see him in a Wallabies jersey.

"I know he's coming back from a bit of injury, but just the quality and the class of him as a player, then I can't see why he wouldn't [dominate].

"I don't think the Northern Hemisphere European teams will know what to expect when they see his big afro coming down the sideline because I think he'll slip in under the radar because he hasn't been in a Wallabies jersey and he hasn't been talked about over there.

"Yet here in Canberra we know what he's capable of, so he might sneak up on them and really create a show."