"It's completely false. Jeff is a longtime friend of Gwyneth's and there was no romantic relationship with him at all," a spokesperson for the actress told MailOnline.
"He flew many of his friends to Miami that weekend — not just Gwyneth."
The statement comes after it was claimed that their friendship might be called into question by Vanity Fair, Page Six reports.
Billionaire property mogul Jeff married Elle Macpherson in an intimate wedding on the island of Fiji in July in front of around 15 guests.
"They are very happy and head over heels in love," a source told PEOPLE magazine.
The ceremony was attended by Australian-born Elle's two sons Arpad Flynn and Aurelius Cy.
Gwyneth, who is notoriously private about her marriage to Chris Martin, recently opened up about their long-term relationship.
Speaking to Good Housekeeping in July, the actress spoke about her wedded bliss, revealing that the "best decision" she's made was "to marry my husband".
She also discussed the couple's two children , Apple, nine and Moses, seven, in her interview, admitting they are her best achievement to date.
"I was really lucky to have two healthy children, and I enjoy the process of raising them and watching these amazing human beings start to come out and be themselves."
In May, she admitted to Glamour magazine that her relationship with musician Chris has been through some tough times.
"It's hard being married," she said. "You go through great times, you go through terrible times. We're the same as any couple."
She also revealed she had turned to her father for advice. "I asked my dad once, 'How did you and Mum stay married for 33 years?' And he said, 'Well, we never wanted to get divorced at the same time.' And I think that's what happens. When two people throw in the towel at the same time, you break up, but if one person's saying: 'Come on, we can do this,' you carry on.
"I've learned more about myself being married than anything else. I hate to say, 'We've got it worked out,' because you never know what's going to happen, but we laugh, we're good friends, we like to do the same stuff."
Gwyneth and Chris are set to celebrate their ten year wedding anniversary in December.