Tyson Fury to Anthony Joshua, 'Grow a Pair and Sign the Contract'

Tyson Fury says he's "optimistic" he will fight Anthony Joshua in 2021 -- telling his rival, "Grow a pair and sign the contract, Big Boy!"

The Gypsy King appeared on "Good Morning Britain" where Piers Morgan referenced a report that the fighters could sign a 2-fight deal worth more than $500 MILLION!!!

"Well that doesn’t sound too bad," Fury said ... "but then again, I don’t believe everything I see in the paper."

"Let’s hope this fight happens. I’m willing to take the fight, I don't know if they are. I’ve been willing to take the fight for the last 5 years. It’s not happened so far but I’m very optimistic that will happen in 2021."

Of course, Joshua is coming off a violent victory over Kubrat Pulev -- he demolished the heavyweight Saturday night with a 9th-round knockout.

After the fight, Joshua was asked about a possible matchup with Fury -- and Tyson wasn't satisfied with his answer!

Tyson even mocked AJ on social media -- "Anthony Joshua just sh*t himself live on television! He got asked did he want the fight … and he went around the bushes and put his ass on the edge!"

"I want the fight! I want the fight next! I'll knock him out inside 3 rounds! He's a big bum dosser, I can't wait to knock him out!"

31-year-old Joshua is 24-1 as a pro with his only loss coming by way of Andy Ruiz. He defeated Ruiz handily in the rematch.

32-year-old Fury is 30-0-1 -- with his 1 draw coming by way of Deontay Wilder. He smashed Wilder in the rematch.