The pair, who wed in a lavish ceremony last year, have been the subject of reports they are "leading separate lives", and Michelle has also been pictured without her wedding ring.
However, representatives for the couple have insisted that they are still very much happily married.
"Of course they're together," Mark's spokesperson told new! magazine, with Michelle's rep adding: "We won't be commenting on Mark and Michelle's relationship."
Michelle is currently away filming the new series of BBC drama 'Our Girl', having jetted out to South Africa in March.
While Mark has just returned from a 10-day trip to visit his wife, along with his parents, fans were concerned they had not posted any pictures of their reunion on social media.
Various publications also spotted Michelle wasn't wearing her wedding ring or £20,000 engagement rock in pictures that showed her letting her hair down with her male co-stars.
Speaking about the role in her Hello magazine blog, she revealed she had been embracing army life.
"I've learnt how to hold and fire a gun which felt amazing – serious adrenaline rush, and by the way, they are really loud!" she said.
"I have also learned to pack a medical kit and how to extract a casualty to safety."
'Our Girl' is set to air on BBC One later this year.
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