Simon Cowell is ''absolutely delighted'' Louis Tomlinson is set to become a father.

The music mogul, who has 17-month-old son Eric with girlfriend Lauren Silverman, was one of the first people the One Direction star contacted three weeks ago after learning Los Angeles-based stylist Briana Jungwirth is pregnant with his child.

A source said: ''Simon was one of the first people Louis called after he'd told his family. Louis was so excited and he wanted to tell Simon himself.

''Simon was absolutely delighted for Louis and told him that becoming a dad was the best thing that had ever happened to him. He told him if he ever needed any advice to let him know.''

The 'X Factor' boss, 55, has assured the 23-year-old singer he will be there to support him as much as possible when Briana, 23, gives birth early next year and has already given him lots of parenting tips.

The insider told PEOPLE magazine: ''Simon knows Louis already has lots of experience with babies and adores kids. Louis' youngest twin brother and sister are only 17 months old and he's incredibly close to all of his seven siblings -- and his mum is a midwife.

''But adjusting to being a dad will be a change, of course, so having Simon's advice when he needs it means a lot to Louis.''

Louis and Briana met through mutual friends earlier this year and while they ''aren't in a relationship,'' the duo are said to be very happy to be expecting their first child.