King Felipe's brother-in-law, Iñaki Urdangarin, has been pictured hand-in-hand with another woman while his wife, Infanta Cristina de Borbón, remains living in Switzerland.
The photographs published by Spanish publication Lecturas, show the former handball player, 54, walking along a beach with an unknown woman.
Sources have told HELLO!'s sister publication, HOLA!, that the photographs of her husband have not caught Infanta Cristina, 56, by surprise and that "she already knew".
READ: Kate Middleton returns to royal duties for joint outing with Prince William in London
WATCH: Queen Letizia showcases flawless newsreader skills
Meanwhile, the couple's second son, Pablo Urdangarin, 21, told the press: "We are all going to love each other the same."
Iñaki and Infanta Cristina were last pictured publicly together last month in photos published by HOLA! as they enjoyed a family holiday in Baqueira Beret. The couple, who married in 1997, share four children, Juan, Pablo, Miguel and daughter Irene.
In June 2018, King Felipe's brother-in-law was given a five year and ten-month prison sentence following convictions of embezzlement and money laundering in excess of £4.5 million through his non-profit organisation, the Noos Institute.
Last year, Iñaki was granted permission to move to Spain's tercer grado or Grade 3 prison regime, meaning that he only reports to prison once a week.
MORE: Prince Andrew deletes social media accounts after being stripped of titles
MORE: Boris Johnson publicly apologises to the Queen over No10 parties held the night before Prince Philip's funeral
Infanta Cristina and husband Iñaki pictured in 2019
Infanta Cristina was also investigated but acquitted of any charges. However, King Felipe issued a decree stripping his sister of the title of Duchess of Palma in 2015.
She is the youngest child of former King Juan Carlos I and Queen Sofia, and remains sixth in line to the throne behind her older sister, Infanta Elena, Duchess of Lugo, and her two children,
King Felipe stepped out for a joint engagement with his wife, Queen Letizia, on Wednesday as they visited the FITUR Tourism Fair 2022 in Madrid.
Make sure you never miss a ROYAL story! Sign up to our newsletter to get all of our celebrity, royal and lifestyle news delivered directly to your inbox.