ALEC BALDWIN’s upcoming marriage to pretty young HILARIA THOMAS has devastated his emotionally fragile ex-wife KIM BASINGER.

Kim is convinced the union will drive a painful wedge between her and 16-year-old daughter Ireland, who has been bonding more and more with Hilaria, say sources.

The 58-year-old actress, who has admitted she suffers from panic attacks and agoraphobia (fear of being in public places), has already been coping with fears that the teen has more in common with her hip new future stepmother.

Hilaria, a former Latin dancer who teaches a type of yoga she says enhances sexual pleasure, is just 28 and nearly half Alec’s age. He’s 54. Ireland, who’s physically fit, tall and thin, is into sports and working out.

“Kim is incredibly jealous of how crazy Ireland is over Hilaria and feels she’s being pushed out of her daughter’s world,” said a family friend.

“She is still a beauty but no longer the gorgeous sex symbol who stole Alec’s heart. And her movie roles fall far short of the Oscar-winning one she had in ‘L.A. Confidential.’”

Hilaria has already stepped up up mom-like when she helped to mend a rift between Ireland and her father after he blasted her in 2007 on a voice mail as a “rude, thoughtless little pig” – a vicious attack that made national headlines.

“Hilaria worked hard to win over the youngster and heal the father-daughter breech,” said the friend. “But that made Kim feel like an outsider.”

Even Kim’s own mother, Ann Basinger, admitted there’s a special bond between Hilaria and Ireland.

“Alec would not have proposed marriage if Ireland had not given her approval – and she did,” Ann told The ENQUIRER. “The ladies have a lot in common: They both love Alec. They get along great.”

Hilaria and the “30 Rock” star are set to walk down the aisle June 30, and friends say the two are truly in love. Said one pal: “Everyone in Alec’s world thinks she’s wonderful – ex­cept Kim.”