Dec 17 (Reuters) - Shares in Belgian state-controlled telecoms firm Proximus rose on Friday after its subsidiary TeleSign agreed to merge with a New York blank-cheque company in a deal that would value the unit at $1.3 billion.

U.S.-listed North Atlantic Acquisition Corporation (NAAC) , chaired by Diageo's former Europe chief Andrew Morgan, said on Thursday it would buy a minority stake in TeleSign for a total transaction size of $487 million.

NAAC said it would raise another $107.5 million to complete a deal.

Proximus shares were up 4% to 17.66 euros at 1122 GMT.

"By facilitating TeleSign's intended introduction to public equity markets we can accelerate its next phase of growth, addressing the underserved digital identity and engagement space," NAAC CEO Gary Quin said in a statement.

California-based TeleSign helps businesses to secure their digital identities, prevent fraud and establish secure communications.

Blank-cheque or special purposes acquisition companies (SPACs), are cash vehicles that are listed on stock markets and backed by well-known entrepreneurs that are then used to buy a private company, thus providing an alternate route to a listing than an initial public offering.

A record $130 billion plus of SPACs have listed globally this year, most in New York, many of which are now on the hunt for targets; a lucrative opportunity for private companies looking for a relatively easy route to a public listing.

Proximus said it was not selling any of its shares and would own 66.5% of TeleSign upon completion of the transaction.

The transaction is expected to close in the second quarter of next year.

TeleSign said it expected to generate $391 million of revenues in 2021, with an expected increase to approximately $1.1 billion in 2026. (Reporting by Anait Miridzhanian Editing by Abhinav Ramnarayan and Mark Potter)