It costs $65-per-hour to spy on your ex-husband ... this according to a private eye who claims he spent months snooping around for "Gossip Girl" star Kelly Rutherford ... only to get stiffed when the bill came.

The divorce between Rutherford and her ex-husband Daniel Giersch was EPICALLY NASTY -- with restraining orders and allegations of child endangerment.

According to a lawsuit, obtained by TMZ, Rutherford hired a private eye to spy on her ex in April 2010 ... "in relation to certain issues regarding child custody and other matters."

The private eye, Edward Banach, claims he worked on the case for a couple of months ... racking up a total bill of $86,249.85 ... but only got paid $28,214.35.

Now, Banach -- who was sub-contracted through a now-defunct security company -- is suing the business AND Rutherford to get the remaining $58k. 

FYI -- At the height of the legal war between Kelly and Giersch, the actress admitted she hired a P.I. ... to prove her ex didn't properly secure the pool and play areas at his home -- which she said endangered the couple's 2-year-old son Hermes.

Rutherford explained, "I was concerned about my son's safety."

We called Kelly for comment on this story -- so far, no response.

Kelly Rutherford from "Gossip Girl" can kiss her epic divorce battle goodbye -- because TMZ has learned her split with hubby Daniel Giersch is 100% official. 


According to documents filed last week in L.A. County Superior Court, Kelly -- who was pregnant when she filed for divorce in December of last year -- was officially deemed a free woman as of June 6.

In the docs, it also shows Kelly's last name was changed back to Rutherford from Giersch.

Kelly and Daniel -- who've been fighting over custody of their two children -- were only married for around 2 years.

After one of the nastiest splits in the history of Hollywood, "Gossip Girl" star Kelly Rutherford called a temporary truce with her estranged husband Daniel Giersch this weekend -- so baby daddy could spend some time with their 2 kids.



Earlier this month, Kelly dropped the restraining order against Daniel -- but yesterday in L.A., the two agreed to act like civil, peace-loving people so Kelly could drop off the kids.

Baby steps.

TMZ has learned Kelly Rutherford was granted a temporary restraining order against her ex Daniel Giersch.

According to documents filed in L.A. County Superior Court, Kelly claims Daniel has repeatedly harassed both her and their nanny -- which she claims forced the nanny to quit.

The documents list Giersch as 39-years-old, white, and "thin."

Geirsch must stay 100 yards away from Kelly, her mother, the nanny, and Kelly's home, job and vehicle -- "except for brief & peaceful contact as required for court-ordered visitation."

In the docs, it says "Daniel has begun to follow me, my mother, my nanny and he shows up unexpectedly to threaten and scare us."

Kelly also claims Daniel "has harassed [my nanny] with questions about me virtually every time he sees her ... last week Daniel's harassment of [the nanny] led to an actual threat that he is going to file a lawsuit against her."

After that, Kelly says the nanny handed in her pink slip, causing her two kids -- Hermes and Helena -- to lose someone they "love and trust."

Kelly Rutherford just settled her custody dispute with ex Daniel Giersch -- at least until April 2010.

The "Gossip Girl" matriarch filed for divorce in December 2008. The couple has two children together -- one of whom was born less than two months ago.

Rutherford and Giersch had a heated battle over custody that nearly kept Rutherford from filming scenes for "Gossip Girl."

Settlement documents have been filed with the court. Under the terms, both Kelly and Daniel will temporarily relocate from California to New York while she films "Gossip Girl" -- from July 30 through April 5. She'll live in NYC and he'll live in the Hamptons. Neither party can travel outside of New York or California without the agreement of the other.

The docs say both parents will attend co-parenting counseling sessions.

They will share joint legal and physical custody of the two kids.

Another "Gossip Girl" star in the news. Kelly Rutherford is apparently worried that her ex might leave the country with the couple's two children, Hermes and Helena.

We got our hands on docs filed yesterday in their custody war -- both Rutherford and her estranged hubby Daniel Giersch have agreed he will ante up his visa and visa application to her lawyer within a week.

The docs don't say why this is happening, but the application is telling -- it seems Giersch may have plans to leave the country, smack in the middle of their ongoing fight over the kids. Giersch is from Germany.

In a move straight out of the Bart Bass playbook, "Gossip Girl" star Kelly Rutherford hired a detective to videotape her ex -- but today outside court, she insisted it was only to check in on "my son's safety."


Rutherford hired the private eye to prove her ex, Daniel Giersch, didn't properly secure the pool and play areas at his home -- which she said endangered the couple's 2-year-old son Hermes. She also wanted Daniel to stop potty training the kid.

The judge ordered Giersch to properly cover the pool -- and today in court Daniel proved that had been done. As for the toilet talk, Hermes will continue to use pull-ups and can use a toilet if he so chooses.

"Gossip Girl" star Kelly Rutherford isn't finished with her custody war with estranged hubby Daniel Giersch. She now claims Daniel is putting their kid in danger.



Kelly has filed legal papers asking the judge to prohibit Daniel from taking 2-year-old Hermes to his home until he has properly secured the pool and play areas.

She also wants Daniel to stop potty training the kid, stat. She doesn't say why.

The judge has set a hearing for Friday. In the meantime, the judge has ordered Daniel to properly cover the pool.

"Gossip Girl" matriarch Kelly Rutherford just arrived at the L.A. County Courthouse to square off with soon-to-be-ex hubby Daniel Giersch in what has become a legal hate-fest.


Giersch didn't want their two-year-old son, Hermes Gustaf, to travel with Kelly to NYC to film "Gossip Girl." The judge allowed the travel temporarily, and today Giersch's lawyer says everyone will probably agree to some permanent custody deal.

Rutherford, who plays Lily van der Woodsen on the show, is pregnant with their second child ... always awkward.

UPDATE -- So much for optimism. Not much went down and nothing was decided. Both sides will back in court to do it all again soon.

Kelly Rutherford with son Hermes looking the opposite of "crazy" on the set of Gossip Girl in NYC Friday.


Her soon-to-be ex husband Daniel Giersch still contends Kelly is too crazed while she's filming, which isn't a good influence on their son.

A judge just ruled Kelly Rutherford can take her kid to NYC while she films "Gossip Girl."


The judge said Kelly can go on Sunday and her estranged hubby Daniel Giersch is free to travel there as well. He had argued he needed to stay in L.A. to do his business, but the judge begged to differ. Daniel told the court he will travel to New York.

Rutherford filed for divorce on December 30. She is also pregnant.

Giersch was awarded two overnight visits per week for the month of February and three per week for March. They all need to come back to L.A. for a minimum of four days, at least twice. During the L.A. stays, Hermes will alternate between the two parents.

The judge also ruled 2-year-old Hermes will bounce between NYC and L.A. for the next two months while the feuding couple tries to hash out a long-term custody arrangement. Good luck.