Donald Trump’s affair with Stormy Daniels is back in the spotlight after the President’s former lawyer, Michael Cohen, raised the scandal in his testimony to Congress last week.

The timing couldn’t be worse for Melania Trump, who on Monday embarked on her first solo domestic overnight trip in her official capacity, a three-state tour to highlight her “Be Best” childhood initiative.

The First Lady was peppered with questions by reporters as she boarded a flight from Washington D.C to Tulsa, Oklahoma, including one from a member of the press pool who asked if she accepted Cohen’s apology for lying to her about President Trump’s infidelity.

Baring her legs despite the temperature being barely above zero, Melania declined to answer as she stepped onto the plane.

In his testimony, Cohen expressed his regret at lying to Mrs Trump about her husband’s affair and the US$130,000 hush-money payment made to Daniels, real name Stephanie Clifford, days before the 2016 presidential election.

“He [Trump] asked me to pay off an adult film star with whom he had an affair and to lie to his wife about it, which I did,” Cohen told a packed Congress.

“Lying to the First Lady is one of my biggest regrets. She is a kind, good person,” he added.

“I respect her greatly and she did not deserve that.”

Mrs Trump’s trip will also likely be overshadowed by a sprawling new probe of the Trump family launched by House Democrats on Monday, which seeks documents from 81 people and entities in relation to the president.

After a visit the Dove School of Discovery, a Tulsa elementary school that the White House says incorporates character education in its curriculum, the First Lady will fly to a Seattle-area tech company later on Monday to learn about programs and apps designed to teach children how to be safe online, and about technology to help children with disabilities.

She’ll then conclude the tour on Tuesday in Las Vegas by participating in a town hall on the opioid crisis.

The first lady launched Be Best last May to focus on child wellbeing, online safety and bullying prevention, and opioid abuse.