Sir Michael Gambon is reportedly to have a second child with his girlfriend at the age of 68.

The veteran actor – who plays headmaster Albus Dumbledore in the Harry Potter films – is delighted his girlfriend, set designer Philippa Hart, 43, is expecting a sibling for their 17-month-old-son, the Sun reports.

A source said: “Michael and Philippa are delighted that she’s pregnant again. Philippa wanted a brother or sister for little Michael because when he gets into its teens, it’s possible Sir Michael might not be around.

“Philippa felt it important her son had a sibling. She’s also in her forties, so this could be the last chance for more kids.”

Sir Michael – currently starring on London’s West End stage in Harold Pinter’s No Man’s Land – lives between Philippa’s home in Chiswick, west London, his bachelor pad in the city, and the family estate in Gravesend, Kent.

The actor shares his family home with his wife, retired mathematician, Lady Anne, who he married 45 years ago. The couple have a 44-year-old son, Fergus, who has appeared as an expert on the BBC’s Antiques Roadshow.

Sir Michael has finished filming sixth Harry Potter movie, Harry Potter And The Half-Blood Prince, due out next July.