The news comes following rumours that her ex-bandmates have been quietly dropped by the US record company, with whom they signed a deal in early 2009.
Buchanan has been busy working on a solo album in recent months after being ousted from Sugababes last September.
A source told The Mirror: "Jay is serious about getting her on board. They hit it off at the Brits after-party in London."
On Sugababes' current woes, the insider added: "Keisha will be gutted that things have not worked out so well for the band she helped create."
Sugababes' latest album Sweet 7 failed to crack the top ten following its release last week.