The couple’s over-the-top declarations of love have left observers asking if the relationship is a publicity stunt.
Throughout his career, Cruise has been deeply protective of his private life. He gave little away about his 10-year marriage to Nicole Kidman and his previous union with Mimi Rogers.
During his three years with Penelope Cruz the couple were seldom seen together, and the actress was lucky if Cruise put an arm around her on the red carpet.
But since going public over his relationship with Holmes, an actress 16 years his junior, Cruise has been behaving like a man possessed.
The 42-year-old star made a jaw-droppingly embarrassing appearance on the Oprah Winfrey Show, jumping up and down on the sofa and punching the ground while yelling: “I am in love, I am in love!”
In fact, the couple seem unable to keep their hands off each other in public.
Holmes, aged 26, has also announced that she is taking lessons in Scientology. The Dawson’s Creek star was raised a Catholic but within weeks of dating Cruise she began studying his controversial religion.
But while the couple appear delighted by their newfound love, the public are less enamoured.
A poll in People magazine found nearly two-thirds of those questioned believed the relationship to be a publicity stunt. One US website is even selling T-shirts and mugs bearing the slogan “Free Katie.”
But the couple have fiercely denied the suggestion their love is a sham.
“I have to laugh. It’s just ridiculous,” Cruise said earlier this week.
Holmes has described Cruise as “the most amazing man in the world.”
The actress has certainly been catapulted into the A-list thanks to Cruise.
Her relationship with Cruise coincides with her role in her first Hollywood blockbuster, playing the love interest in Batman Begins.
She briefly dated co-star Joshua Jackson and was engaged to actor Chris Klein until shortly before she met Cruise.
Cruise married first wife Mimi Rogers in 1987 and went on to marry Nicole Kidman in 1990. The couple had two adopted children, Isabella and Connor, but divorced after 10 years.
His relationship with Spanish actress Penelope Cruz ended last year.
Cruise has been at the top of the Hollywood A-list for the past 20 years thanks to such films such as Top Gun, Jerry Maguire and Mission: Impossible.
His latest, War of the Worlds, is based on the novel by HG Wells and directed by Steven Spielberg.