Gronkowski, the eccentric star known for his play on the field and his playboy lifestyle off it, signed a multiyear endorsement deal with Monster energy drink. Financial terms were not disclosed.
"I feel like this deal was the ultimate deal for me," Gronkowski said in a statement provided to ESPN.com. "Monster Energy just fits my personality. The brand is great and just like the Monster [brand], I like beautiful girls, too."
Monster, the second-largest energy-drink brand in the U.S. behind Red Bull, frequently uses women dressed in its logos at sporting events.
"Rob perfectly fits into our strategy of signing unique, elite athletes," said Mitch Covington, Monster's vice president of sports marketing. "We love what he does in the games, but we also love that he likes to party."
Gronkowski joins the likes of Triple Crown winner American Pharoah, race car drivers Lewis Hamilton and Kyle Busch, and UFC fighters Ronda Rousey and Conor McGregor as major names that have signed deals with Monster.
Doing the deal wasn't that easy -- it required Gronkowski to stop doing endorsements for sports drink Body Armor. Gronkowski will still keep his shares in the company.
Aside from Odell Beckham Jr. and J.J. Watt, no one has done more deals of late than Gronkowski. He has deals with SMS Audio (headphones), Dunkin Donuts and daily fantasy company DraftKings. He is also selling a cruise, called the Gronk Party Ship, which sets sail in February.
In his book, "It's Good To Be Gronk," he said he had lived off only his endorsement money and hadn't spent any of his contract money.