The 39-year-old, who is back in the US for America's Got Talent, was also asked by reporters whether or not Stephen, 39, had ever hit her.
She said: "No, my husband didn't hit me."
Laughing off the "silly rumours", Mel added: "No, I didn't get held hostage."
The Spice Girl then insisted: "Me and my husband are madly in love."
Rumours of trouble in Mel and Stephen's marriage first surfaced in December, when she was absent from the first part of The X Factor final after being rushed to hospital.
When she returned for the second part of the final, fans on Twitter we're quick to notice Mel wasn't wearing her wedding ring.
Then last month it was reported that, days before being taken into hospital, Mel was held against her will at their £4 million London home.
But a spokesperson for Mel at the time blasted the allegations that she had called the police on Stephen.
They said: "Both Mel and Stephen categorically deny this is true and the police have not contacted Stephen."
A source told the Mirror: "Stephen and Mel both feel like someone out there has a vendetta against them.
"They're both really confused about the rumours that have been flying about, and who started them.
"They had a small rocky patch before Christmas but are completely sorted and happy again now."
From Spice Girls to X Factor: Mel B's life in pictures
1 of 29Melanie Janine Brown
Since her rise to fame as Scary Spice in the early 90s, Mel B has been no stranger to controversy. She's gone through marriages, divorces, paternity tests and managed to remain the crazy singer we all love. Here's her life in pictures.
2 of 29melanie2
Born 29 May 1975.
3 of 29melanie3
Mel was born in Harehills, Leeds and grew up in nearby Burley, and has a younger sister Danielle.
4 of 29melanie4
She studied performing arts at Intake High School.
5 of 29melanie5
After responding to a newspaper ad in 1993, Mel won a part in a girl group called Touch.
6 of 29melanieold
She and Melanie C, Emma Bunton, Geri Halliwell and Victoria Adams spent two years showcasing for A&R men and producers.
7 of 29melanie6
In 1995, Touch became the Spice Girls.
8 of 29melanie7
The girls released their first single Wannabe in 1996, which was a global hit.
9 of 29melanie8
While on tour with their second album, Mel began dating dancer Jimmy Gulzar.
10 of 29melanie10
Mel and Jimmy's daughter Phoenix Chi was born in February 1999.
11 of 29melanie11
She filed for divorce from Jimmy in 2000, leading to a custody battle for Phoenix Chi. Mel won, but had to pay Jimmy an estimated $2.8million.
12 of 29melanie13
Spice Girls went on hiatus in 2000, after selling 75 million records worldwide and booming one of the most successful music acts of all time.
13 of 29melanie14
Mel released her debut solo album Hot in 2000, which spawned for top 10 singles.
14 of 29melanie15
Following poor single sales, Mel was labelled Desperate Spice by the press when she featured Phoenix Chi in the video for her fifth single Lullaby.
15 of 29melanie16
In 2006 Mel began a highly publicised relationship with actor Eddie Murphy, and it was reported later that year she was expecting his baby.
16 of 29melanie17
Following their split, it was confirmed by DNA test in 2007 that Mel's second daughter Angel was Eddie Murphy's – though he initially denied this. After 'reimbursing' the cost of the pregnancy, Eddie also handed over $7million.
17 of 29melanie18
Mel took part on US reality show Dancing With The Stars, finishing runner-up.
18 of 29melanie19
She started a relationship with Stephen Belafonte in February 2007.
19 of 29melanie20
The couple married in secret in June 2007.
20 of 29spicegirlsreunion
That year, the Spice Girls also regrouped and announced plans for a reunion tour. They reportedly earned £10million each.
21 of 29melanie22
Following the tour, they all appeared in Tesco television adverts.
22 of 29melanie23
In 2011 Mel was announced as a judge on the Australian X Factor.
23 of 29melanie24
Stephen and Mel welcomed their first child together, daughter Madison, in September 2011.
24 of 29melanie25
Mel and Stephen starred in their own US reality show, It's a Scary World, in 2012.
25 of 29melanie26
That year, it was announced Mel would appear as a guest judge on The X Factor UK.
26 of 29melanie27
In 2013 Mel replaced Sharon Osborne as a judge on America's Got Talent.
27 of 29melanie28
Mel released her first single in eight years in September 2013, titled For Once In My Life.
28 of 29melanie29
She became a full time judge on The X Factor UK in 2014.
29 of 29melanie30
After getting pregnant with Jimmy's baby, they married in September 1998, leading to Mel changing her name to Melanie G.