Len stepped down from Strictly Come Dancing ahead of last year’s series and as yet the BBC hasn’t chosen a replacement.
Screen tests were reportedly held at the Strictly studio in Elstree last week with both some familiar and surprising faces.
The likes of pro dancers Anton Du Beke and Brendan Cole both tried out as did former professional former and It Takes Two regular Karen Hardy.
Others who auditioned included Ireland’s Dancing with the Stars judges Loraine Barry and Brian Redmond as well as Strictly's current head choreographer Jason Gilkison.
But The Sun newspaper reports that ballroom dancer Shirley - who's son Mark Ballas is a pro dancer on the American version of Strictly - proved to be the standout of the unaired try outs.
"Shirley had by far the best screen test and was a natural," a source told the newspaper. “Producers want her to replace Len because of her wealth of experience both in the dance world and already being a judge on the telly.
“But nothing has been signed off yet — top BBC bosses have to give the final approval as this has become its biggest talent job vacancy.”
A spokesperson for the BBC said: "As yet no one has been offered the role of Strictly’s new judge.”
The new series of Strictly Come Dancing will air on BBC One later this year.
Celebrity names tipped for this year's cast include Good Morning Britain presenter Charlotte Hawkins, Gogglebox stars Steph and Dom Parker, Olympic gymnast Max Whitlock, footballer Frank Lampard and Olympian Jessica Ennis-Hill.