Tom Brady wore a diamond-covered Rolex Sea-Dweller worth an estimated $6 million on “The Roast of Kevin Hart” on Sunday. Getty Images for Netflix The real knockout at Kevin Hart’s roast was on Tom Brady’s wrist. The retired quarterback showed up as a surprise guest at “The Roast of Kevin Hart” on Netflix Sunday night wearing an accessory that hit just as hard as his punchlines. Brady, 48, posted a closeup of his diamond-drenched watch in an Instagram carousel after the show at the Kia Forum in Inglewood, California, writing, “Payback is a bitch 😂😂 @kevinhart4real.” The off-catalog timepiece in 18-karat white gold is fully set with baguette-cut and square-cut diamonds across the bracelet. Getty Images for Netflix Brady posted a closeup of the watch to Instagram after the show, captioning it, “Payback is a bitch.” Getty Images for Netflix Watch enthusiasts have valued the rare gem-set Sea-Dweller at upwards of $6 million, though exact figures remain in dispute.…