The Game Of Thrones star, 43, and ex Peter Loughran, whose six year marriage ended in 2013, became embroiled in a bitter legal spat after she relocated to the U.K. with their six-year-old son Wylie and her 17-month old daughter Teddy.
Loughran claimed she had violated a 2013 custody agreement by enrolling Wiley into school in Britain without seeking his permission, with a judge ruling in his favour in October (16).
A court filing obtained by TMZ.com reportedly shows Loughran is demanding his ex-wife pay $40,000 (£31,510) in legal fees, as he is unemployed while Lena is earning huge sums from her role as evil royal Cersei Lannister in the hit HBO fantasy TV show.
The documents reportedly claim she earns more than $1 million (£790,000) for each episode of Game of Thrones, whose seventh season begins next year (17).
In the October ruling, a Los Angeles family court judge told Lena to return her son to the U.S., but allowed her to keep him with her in the U.K. until the next period of filming finishes on Game of Thrones early next year (17).
According to TMZ, the actress' former spouse is allowed to visit Wiley for 10 days every month and she was ordered by the court to pay any travel expenses he incurred by seeing his son.
The court is yet to rule on Loughran's new demands.
Lena and the musician separated in 2011, but the divorce was only finalised in 2013 after a lengthy dispute over custody and financial issues, which was only initially resolved when they struck a deal to share joint legal custody of Wylie.