Two-time Oscar winner Robert De Niro's estranged second wife Grace Hightower revealed she wants half of his $500million fortune while at a Manhattan Supreme Court hearing on Thursday.

However, the 64-year-old former TWA flight attendant signed a prenuptial agreement in 2004 limiting her to a $6million apartment, $500,000 cash, and $1million in alimony - according to Page Six.

Grace's attorney Allan Mantel argued that the prenup's language entitled her to half of what the 75-year-old acting legend earned during the remarriage, including from his '35 businesses.'

Nickel and diming? However, the 64-year-old former TWA flight attendant signed a prenuptial agreement in 2004 limiting her to a $6M apartment, $500K cash, and $1M in alimony (pictured in 2018)

Aside from his thriving movie career, Robert owns the Greenwich Hotel, the Nobu/Tribeca Grill restaurant chains, Tribeca Film Festival, and Canal Productions.

Bitter split: Grace's attorney Allan Mantel (R) argued that the prenup's language entitled her to half of what the 75-year-old acting legend earned during the remarriage, including from his '35 businesses' (pictured February 7)

Career-wise, Hightower has dabbled in acting, singing, and philanthropy; and she founded Coffee of Grace six years ago 'to help rebuild the economy of Rwanda.'

It's technically the second divorce for the acrimonious couple - who met in 1987, wed in 1997, filed for divorced in 1999, renewed their vows in 2004, before splitting for good in November.

June 17 would have marked the 22nd wedding anniversary for the pair, who are parents to 21-year-old son Elliot and seven-year-old daughter Helen Grace (whom they're fighting for custody).

De Niro has two children - adopted daughter Drena, 47; and son Raphael, 43 - with ex-wife #1 Diahnne Abbott, whom he divorced in 1988 after 12 years of marriage.

The native New Yorker also has twin 23-year-old sons Aaron Kendrick & Julian Henry with his babymama, former fashion model Toukie Smith.

The De Niros are also battling over custody of their seven-year-old daughter, Helen Grace.

Hightower (pictured left on May 13) has dabbled in acting, singing, and philanthropy; and she founded Coffee of Grace six years ago 'to help rebuild the economy of Rwanda'. De Niro, a father of six, is pictured (right) with his adopted daughter Drena , 47. He also has son Raphael, 43; with ex-wife #1 Diahnne Abbott, whom he divorced in 1988 after 12 years of marriage

Babymama: The native New Yorker also has twin 23-year-old sons Aaron Kendrick & Julian Henry with former fashion model Toukie Smith (pictured September 29)

'Grace and I have two beautiful children together. We are entering a period of transition in our relationship which is a difficult but constructive process,' the two-time Golden Globe winner said in a statement.

'I honor Grace as a wonderful mother and ask for privacy and respect from all as we proceed to develop our roles as partners in parenting.'

In 2016, Robert released a statement to the public explaining that their 21-year-old son Elliot had been diagnosed with autism.

At the time, there was controversy around an anti-vaccination documentary that was set to be screened at the actor's Tribeca Film Festival. The film was later pulled.

'Grace and I have a child with autism and we believe it is critical that all of the issues surrounding the causes of autism be openly discussed and examined,' the Lee Strasberg alum said in a statement.

The Casino star is notoriously private about his relationship with Grace but the pair had been outspoken in the past about their belief that Elliot's autism is linked to vaccinations.

Grace was quoted saying that her son 'changed overnight' after being vaccinated as a child, Robert told Today in 2017: 'The vaccines are dangerous to certain people who are more susceptible...

'Nobody seems to want to address that, or they say they've addressed it and it's a closed issue but it doesn't seem to be.'

'There are many people who will come out and say I saw my kid change overnight. I saw what happened, I should have done something and I didn't. There's more to this than meets the eye, believe me.'

The SNL guest star next plays talk show host Murray Franklin in Todd Phillips' Joker - hitting US/UK theaters on October 4 - alongside Joaquin Phoenix, Zazie Beetz, and Frances Conroy.