The ] studio at Rockefeller Center, and they've gone out to dinner after rehearsals," adds an insider.
PHOTOS: 2011's biggest splits Wilde, whose divorce with Tao Ruspoli was finalized in October, has also been romantically linked to Bradley Cooper, Ryan Gosling and Ryan Reynolds.
However, the pair initially set tongues wagging when Wilde attended a party to celebrate Reynold's cover in LA earlier this month.
News of their reported involvement comes just weeks after Wilde, who filed for divorce from her husband, Italian prince Tao Ruspoli, in February, was seen getting friendly with Jake Gyllenhaal.
We can't get enough of the gorgeous Olivia Wilde and her hunky fiancé Jason Sudeikis — that's a given.
From their undeniable chemistry on whatever red carpet they happen to be strutting on to their adorable obsession with their young son, Otis, this engaged twosome always seems to be in the running for our favorite celebrity couple round-ups.
"He briefly put his arm around her," a witness adds.
PHOTOS: Steamy costar romances Though a source close to the costars denies their lunch date was romantic, the Wilde pal insists: "She'd go out with him again." PHOTOS: Ryan and his ex Scarlett Johansson And how are things with the other woman in Reynolds' life, his confidante Sandra Bullock, 47?
Despite rumours that Ryan and Olivia are dating, representatives for both stars have confirmed they are just friends.
They told Radar Online that the pair “haven’t even seen each other since this past weekend” when they were spotted laughing in each other’s company.
Since then, the actress has been spotted hanging out and flirting with a who’s-who of Hollywood’s hottest eligible bachelors, including Ryan Gosling, Justin Timberlake, Bradley Cooper and Jake Gyllenhaal.
star Olivia Wilde has certainly given the gossips a lot of fat to chew since splitting with her husband, Italian prince Tao Ruspoli, in February.
His divorce from Hollywood beauty Scarlett Johansson was finalised in July of this year.