Heidi Klum says her relationship with her bodyguard "just started".

The supermodel confessed that feelings have developed between her and Martin Kristen, her minder of four years, on American television.

The former Victoria's Secret model was accused of having an affair with Martin by her estranged husband Seal. The 39-year-old insists that although she is involved with him now, she was never unfaithful during her marriage.

"It just started," she told talk show host Katie Couric. "[Martin]'s a great man and recently we just got to know each other from a completely different side."

The German star went on to praise Martin's caring and supportive nature. Heidi trusts him implicitly with the most important things in her life.

"He's been with our family for the last four years. He's cared for our four children and helped us tremendously," Heidi continued. "I trust him with my children's life."

Sources close to the star have explained how close the pair have become.

"Martin is very loyal to Heidi. They had a friendship that turned romantic," a source told People. "He was always her rock, while everything was crumbling in her personal life he was there for her."