AceShowbiz - British actress Vanessa Kirby was "embarrassed" by unfounded rumours suggesting she was secretly romancing her new movie co-star Tom Cruise.

The Crown star, 30, became linked to 55-year-old Cruise while filming the upcoming Mission: Impossible - Fallout in Europe last year (17), but Vanessa never mentioned the tabloid reports to her leading man, because it was just too awkward a subject to broach.

"I don't know where it came from, but I'd met him once in a room full of people (when the romance claims first surfaced), and I was like, 'Well, I move fast!,'" she quipped on talk show The View. "They were reporting that we were dating and I was lining up to be wife number four!".

"Neither of us talked about it, but I felt just embarrassed...," she said. "It's embarrassing, most of all for him, probably! But then we were filming on the river bank in Paris and our characters have to kiss and the paparazzi took lots of pictures, and then it really was (all over the tabloids), (claiming) I was definitely the (next) wife".

Cruise has been largely single since divorcing Katie Holmes in 2012 after six years as husband and wife. He was also married to Nicole Kidman from 1990 to 2001, and Mimi Rogers for three years in the late 1980s.

Vanessa will be hoping her remarks are enough to silence the relationship claims when they reunite in the coming weeks to promote Mission: Impossible - Fallout, which opens in theatres in late July.