Former WBC cruiserweight world champion Tony Bellew expects a very tough test for Mexican superstar Canelo Alvarez, when he challenges WBA super middleweight champion Callum Smith on December 19th.

After months of speculation, Canelo announced his return on Tuesday. The fight is likely going to land in the state of Texas, with DAZN streaming the contest worldwide.

Smith holds a significant advantage in size and reach, but he struggled in his last fight against John Ryder, who has similar physical dimensions to Canelo. There are some observers who felt Ryder had done enough in that fight to earn a win.

Canelo is coming off a long stint of inactivity, with his last ring appearance taking place in November 2019, when he moved up by two weight divisions to score a knockout of Sergey Kovalev.

One year prior, he blew away Rocky Fielding in three rounds to capture the WBA's "regular" title at 168-pounds at Madison Square Garden in New York City.

While some are tabbing Canelo as a massive favorite in the fight - Bellew expects an extremely difficult task for the four division world champion.

"Make no mistake, Smith is the test of a lifetime for Canelo," Tony Bellew told Sky Sports.

"Smith is bigger in size, stronger, undefeated. Canelo? I'm not so sure he can deal with the size and the pressure that Smith will bring. The biggest shock that Canelo will find? When Callum gets on the inside he is not to be messed with. I think Callum can shock the world.

"He will be a heavy underdog because Canelo is pound-for-pound up there with the big boys. Canelo is the best counter-puncher in boxing and a devastating body puncher. If anyone has the keys to unlock the door, it is Callum."