The former Playboy Playmate and E! reality TV star was spotted with the tattooed rocker in Las Vegas this past weekend.
Madison wore a "Team Benji" shirt to support Madden's celebrity boxing match on Saturday against rocker and radio show host Riki Rachtman. She was also spotted with him again as he deejayed at Moon Nightclub's Bang Tuesdays, People reports.
She also took to Twitter to say, "Whoever's at World's Sexiest Boxer's weigh in better take a pic of him in his underwear for me." Shortly after Madden won the brawl, Madison tweeted, "World's Sexiest Boxer Prevails."
E! Online reports, the two celebrated the win at nightclub Wasted Space and were seen having Easter Sunday brunch at Simon at Palms Place.
According to Madison's rep, there is nothing's heating up between the two.
"They are still just friends," the rep says. "Benji happened to be here in town this last weekend so they got to spend more time together than usual," Madison's rep told E! Online.
In earlier reports, Madison said the two are "adventure buddies," and when asked if they're just friends, she says, "something like that."
While she doesn't admit they are dating, the buxom blonde has been gushing about him to the press.
"He's awesome," she told People Tuesday during an appearance at Caesars Palace's Serendipity 3. "He's very hot and very sweet and very smart. He's all the good stuff, all the good stuff rolled up into one."
Madison is filming her E! reality show, "Holly's World," which premieres in June. Madison tells People that there will be no shortage of drama in Sin City and that the show will include "lots of fun Vegas craziness."
The former "Girls Next Door" star and four-time Playboy cover model, was also a contestant on "Dancing with the Stars." Last season, she replaced Jewel at the last minute after the singer suffered fractures in both legs during pre-show training. Madison also sustained injuries during the show.