The 49-year-old Men In Black star released a statement to the press via his publicist after a report in America's In Touch Weekly magazine claimed the pair had separated.
It read: 'Although we are reluctant to respond to these types of press reports, the rumours circulating about our relationship are completely false. We are still together, and our marriage is intact.'
The comment came several hours after Jada denied having affair with her Hawthorne co-star, Marc Anthony.
The 39-year-old addressed industry whispers of a liaison with Jennifer Lopez's ex husband, who joined her TV show as a love interest last year.
'All the rumours regarding Marc Anthony and Jada are false. Completely untrue,' Jada's spokesperson, Karynne Tencer, said. 'As for [the reports of a split between] Will and Jada, I'm not commenting on their personal life.'
According to reports, the couple have now got their legal team involved and are deciding what course of action to take.
A source told RadarOnline: 'Like any other A-list couple they’re used to inaccurate reports sometimes, but when it comes to their marriage, they don’t appreciate anyone demeaning it.
'They’re good sports and they’re laughing about it, but they have to talk about it with their legal counsel to protect themselves,' the source said.
A representative for Anthony also addressed the rumours, saying: 'We unequivocally deny this. Enough is enough. There are families involved, children involved, friendships involved. This is NOT true.'
The Latin star, 42, split from Lopez last month after seven years. They are parents to twins Emme and Max, 3.
In Hawthorne, Jada plays widowed chief nursing officer Christina, who juggles the demands of her career with bringing up a teenage daughter. She is also an executive producer the show.
Anthony was initially introduced as a guest star playing police detective Nick Renata, but is now a series regular. He also serves as the show's executive music producer.
Will's son was the first to defend the Hollywood power couple, who married in 1997.
'Divorce just can't be an option. And I think that's the problem with L.A. - there are so many options. A huge part of the success for [Jada] and I is that we just removed the other options.'
- Will Smith in 2008
Trey Smith, 18, who is the actor's child from his first marriage, tweeted today: 'Will and Jada getting a DIVORCE .. NOT TRUE AT ALL !!'
He later added: #Did #WillandJada split? No they did NOT split ! False information ..its not true RETWEET!!!'
The pair, who earned £20 million between them last year alone, have two children together - Jaden, 13, and Willow, ten.
Will, 40, has been divorced before. He split from Trey's mother - former fashion design student Sheree Zampino in 1995 - after three years together.
Will and Jada first met in 1990 when she auditioned for the his girlfriend on his hit TV show, The Fresh Prince.
She was rejected for the part because she was considered too short.
Jada was a source of comfort for Will after his first marriage ended and in 1997, they wed in a lavish ceremony at a mansion near her hometown of Baltimore in front 100 friends and family.
She was two months' pregnant with their son at the time.
The Question is, Why are we seeing many Divorces in 2011....
Besides that, is Marc Anthony using Jada Pinkett as a Consolation Price....
The Reckless Family 4 ever...