Celine Dion is a doting mum to three sons who she shares with late husband René Angélil. And while the My Heart Will Go On hitmaker is relatively private about her personal life, she delighted fans on Monday after sharing a rare photo with her firstborn, René-Charles.MORE: Celine Dion pays moving tribute to husband on the anniversary of his deathThe Canadian singer posted a picture of herself and her oldest child to mark his 20th birthday.