The 24 star, 42, was charged with third degree assault after allegedly headbutting Proenza Schouler designer Jack McCollough and breaking his nose during a party in New York in May. Kiefer is now in the clear after McCollough refused to co-operate with prosecutors.

Several weeks after the incident, the pair issued a joint statement saying they had resolved their differences.

Manhattan District Attorney spokeswoman Alicia Maxey Greene confirmed that all charges in the case have been dismissed; a statement issued Tuesday reads: “We declined to prosecute after a full investigation. And that included speaking to the complaining witness who was quite uncooperative. Therefore, the D.A. declined to prosecute.”

On NBC’s Late Night Thursday, host Jimmy Fallon managed to get Kiefer Sutherland talking about his most recent criminal collar for headbutting a designer at the MET Costume Gala afterparty in New York City earlier this month.

“It’s something I really regret having happened….”

On Monday, lawyers for actress Brooke Shields released a statement in response to reports that the witnessed the alleged argument — and subsequent headbutting –between Kiefer Sutherland and fashion designer Jack McCollough that lead to the 24 star’s collar on third degree assault charges last Friday.

Kiefer allegedly headbutted the Proenza Schouler designer during a MET Costume Gala afterparty last week.

“A number of statements have been attributed to Ms. Shields in the media that are neither true nor authorized. These statements were obviously made by those who were not in attendance at the party and constitute their version of events,” her lawyers told Entertainment Tonight.

“While at the party she [Shields] was bumped into by Jack McCollough and Kiefer Sutherland became concerned. Kiefer has always been a gentleman in her company. Both Jack and Kiefer are friends of Ms. Shields and she regrets this unfortunate situation,” the statment continued.

This Just In: Kiefer Sutherland has been arrested in connection with an assault earlier this week.

The 24 star — who is currently on probation for a DUI conviction that sent him to jail for more than a month last year– is accused of headbutting Proenza Schouler fashion designer Jack McCollough during an afterparty for the annual costume gala held by the Metropolitan Museum of Art on Monday night.

Sutherland has been charged with misdemeanor assault. The actor was fingerprinted and photographed for a mugshot at the First Precinct in Manhattan on Thursday afternoon.

According to Reuters, actress Brooke Shields may be called in for questioning as a witness because she was at the venue where the alleged altercation took place.

Kiefer Sutherland is expected to surrender to prosecutors on Thursday to face a minor assault charge for headbutting a fashion designer at a MET Costume Gala afterparty in Manhattan Monday.

The 24 actor will be charged with third-degree assault for the attack that left designer Jack McCollough with a broken nose, NYPD sources have revealed to the NY Daily News.

Early reports allege that the confrontation between the men broke out after Jack disrespected model/actress Brooke Shields, prompting Kiefer to defend her honor.

The actor — who is still on probation in California for the 2007 DUI that sent him to County Jail for more than a month — will be issued a desk appearance ticket for the misdemeanor – meaning he won’t be jailed and will be free to travel before his arraignment.

“Anyone who knows Jack McCollough knows that he would not hurt a fly,” a rep for McCollough, who heads NYC’s prestigious Proenza Schouler fashion house tells PEOPLE. “All we can say at this point is that he was the victim of a vicious, violent, unprovoked assault and that the matter is in the hands of the authorities.”

The NYPD is investigating the incident. Kiefer, the star of FOX’s 24, is currently on probation in California stemming from his 2007 collar for DUI.

Kiefer Sutherland is in trouble with the law again after the 24 star headbutted a fashion designer and broke his nose at an after-party for New York’s Metropolitan Museum of Art’s Costume Institute Gala at nightspot SubMercer Monday night.

Television’s Jack Bauer reportedly got into an altercation with Proenza Schouler designer Jack McCollough after seeing him knock actress Brooke Shields to the ground. Kiefer reportedly asked Jack to apologize, prompting the designer to push Kiefer. Kiefer retiliated by serving Jack with a knock in the head.

The designer was taken to hospital where he is still receiving treatment.

However, reps for Brooke deny she was involved in the incident, saying, “Nothing happened to her. Jack did nothing inappropriate. It’s not clear what caused Kiefer to do what he did. Jack did absolutely nothing to her.”

Police are currently investigating the incident, and Brooke will reportedly be interviewed by officers Wednesday.

Kiefer, 42, was jailed for 48 days in 2007 after pleading no contest to driving under the influence (DUI). He is currently on probation.

A history of drunk driving gets you a star on the Hollywood Walk of Fame!

Actor Kiefer Sutherland attended a ceremony honoring him with a star on the Hollywood Walk of Fame on Tuesday.

Kiefer sits with dad Donald Sutherland.

Born:
December 21 1966, London.

Famous for:
What is he famous for? Son of Donald Sutherland and the famous Jack Bauer of hit series 24 (although many fans would agree that the last season was somewhat lackluster). Before he was Jack Bauer he made movies such as Flatliners, Young Guns, A Time to Kill and Stand by Me.

What went wrong?
Sutherland has been known for his partying ways long before Paris Hilton came along and reinvented the term. But he stayed under the radar until he was arrested for DUI in September of last year. It was his 2nd DUI arrest.

Some rumors suggest that several episodes of 24 had to be rewritten to incorporate Sutherland’s partying injuries into the plot.. Sutherland was sentenced to 48 days in jail and the plan was to do his sentence before and after the production of 24 wraps up. However because of the writers strike and suspended production, he spent all 48 days in jail in one go. He was there for Christmas, New Years and his birthday and had one visitor. He spent his time doing laundry duty.

Kiefer Sutherland Video:

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Kiefer Sutherland will be released from jail on Monday, the Glendale Police Department confirms.”He will most likely be released in the early morning, according to authorities. The “24″ star checked into jail in Glendale, CA in December to serve a 48-day sentence stemming from the most recent in a series of DUI arrests.