The odd couple struck up a romance while appearing as judges on U.S. TV talent show The Voice last year (15) and they have been dogged by marriage rumours for weeks.
A new RadarOnline story suggests Blake is in talks with bosses at The Voice, who want him to announce his engagement to Stefani on the show, when it returns to TV next month (Sep16).
One source told the outlet, "Executives are really pushing for an on air engagement!"
But insiders tell GossipCop the tale is ridiculous, and a rep for Stefani insists the report is "made up", while Shelton's spokesperson calls it "nonsense".
The unfounded rumours emerge less than a week after Blake and Gwen were said to have hired top wedding planner Jerri Woolworth to help organise their top-secret nuptials, and the event guru only fuelled the claims by telling TMZ.com she had "no comment" about the report.
Gwen previously played down speculation she and Blake are secretly engaged during a radio interview on 94.7 Fresh FM's The Tommy Show in June (16).
"Let's just take it one day at a time," she shrugged when asked about the claims. "Everything's crazy right now so no, absolutely not."
Both stars have been married before - Gwen to Bush frontman Gavin Rossdale, and Blake to fellow country singer Miranda Lambert. The two couples split last summer (15), before Gwen and Blake embarked on their new romance weeks later.