Elson is devastated by White's eagerness to comfort the BRIDGET JONES' DIARY star, and is terrified the old flames reignite their earlier passions.
Oscar-winner Zellweger dated White on-and-off for two years, and split only a few months before she married country singer Kenny Chesney in a secret beach ceremony in May (05).
Despite warning Zellweger against the whirlwind marriage, White then followed in her footsteps and secretly wed Elson in June, just four months after they met.
A source tells UK newspaper the Daily Star, "Karen is absolutely horrified. Jack dropped everything to be by Renee's side, and Karen only found out after he'd left.
"She knows that although Jack is very fond of her she'll never measure up to Renee. And she's terrified he will rekindle his romance with her."