Robin Thicke, 40, and girlfriend, 22, expecting a baby – on his late dad's birthday

Robin Thicke and his girlfriend April Love Geary are expecting their first baby together. The 22-year-old mum-to-be announced the exciting news on Instagram, alongside a photo of her sonogram, and revealed the new arrival is due on the same day as Robin's late father Alan Thicke's birthday. "Robin and I are very excited to share with you all that were having a baby. The due date is March 1st, Alan's birthday!" she told her fans. April has also given fans their first glimpse of her baby bump, uploading a bikini snapshot taken during her holiday in Hawaii. "Happy in Hawaii with my lil peanut," she wrote alongside.

April Love Geary has given fans their first glimpse of her baby bump

Robin, 40, is already a father to seven-year-old son Julian, with his ex-wife Paula Patton. He started dating April in the months following his separation in February 2014; Paula went on to file for divorce in October that same year, and in March 2015 their split was finalised.

April and Robin made their first public appearance together in May 2015 at a party in Cannes. They have been inseparable ever since, and often post sweet messages to each other on Instagram. The model also proved a big hit with Robin's father Alan, who told E! News in 2015: "She's lovely. [He has an] album coming out and April is there and supportive. We like her a lot." Of the couple's 18 year age difference, Alan's wife Tanya added: "The apple doesn't fall far from the tree! She's a very mature young lady. A very beautiful, smart, mature young lady."

© Photo: Getty Images

Robin Thicke pictured with his late father, Alan Thicke

Alan died suddenly in December, after suffering a heart attack while playing hockey with his 20-year-old son Carter. In the wake of his loss, Robin took to Instagram to pay tribute to the Growing Pains star. "My father passed away today. He was the best man I ever knew. The best friend I ever had," he wrote. "Let's all rejoice and celebrate the joy he brought to every room he was in. We love you Alan Thicke. Thank you for your love. Love, your grateful son."