Odds on the second royal baby being called Sam have been slashed , following the success of Sam Waley-Cohen at Aintree , the Duchess ' close friend . Prince George 's brother or sister could be called Sam - after the jockey that helped the Duke and Duchess of Cambridge rekindle their romance . Bookmakers have slashed odds on the name Sam - which could be used for Samuel or Samantha - being chosen for the name of the second royal baby . It follows the success of part-time jockey and the Duchess of Cambridge 's close friend Sam Waley-Cohen at Aintree this weekend . The 33-year-old amateur jockey was once dubbed 'The Royal Matchmaker ' after he helped the couple rekindle their romance during their brief split in 2007 . The Duke and Duchess of Cambridge have publicly insisted that even they do not know what sex their second child will be . Ladbrokes confirmed they received a recent flurry of bets following Mr Waley Cohen 's high-profile win on Radjhani Express on Friday in Aintree 's Crabbies Topham Chase - prompting their odds to tumble from 66/1 to 20/1 . David Williams of Ladbrokes said : 'With Sam Waley-Cohen 's close links to the Royals it seems punters are putting two and two together and coming up with Sam as their answer for the baby 's name . ' Simon Clare , from bookmakers Coral , confirmed they too have had no choice but reduce their odds on 'Sam ' in recent days because of the popularity of the name . He explained : 'We have slashed his odds from 66/1 to 40/1 . 'Given how close the Duchess of Cambridge is to Sam Waley-Cohen we are also seeing money for Sam or Samuel at 150/1 and Samantha at 200/1 to be their second baby 's name . ' Scroll down for video . The new prince or princess will be fourth in line to the throne but , unlike Prince George , he or she is not expected to rule as sovereign . The baby will be the Queen 's fifth great-grandchild . Alice is still the favourite at 3/1 followed closely by Elizabeth and Charlotte at 5/1 and 6/1 respectively , according to Ladbrokes on Sunday afternoon . At the moment odds have been slashed for female names , because of widespread speculation that the Duchess of Cambridge will give birth to a sister for Prince George . The Duchess of Cambridge is expected to give birth later this month , with a rumoured due date of April 25 . Mr Waley-Cohen , pictured in 2014 , rode to success at Aintree on Friday and in the Grand National . Mr Waley-Cohen , who has been a close confidante of the Duchess of Cambridge for years , rode Oscar Time to 15th place in yesterday 's Grand National . In 2011 he was invited to the couple 's Westminster Abbey wedding . And in 2012 Mr Waley-Cohen- whose relatives include Shell Oil founder , the 3rd Viscount Bearsted - made the Duchess guest of honour at his nuptials to party-organiser Bella Ballin . Mr Waley-Cohen , a part-time jump-jockey and healthcare businessman , won the Cheltenham Gold Cup in 2010 on 'Long Run ' The royal baby is expected to arrive later this month . There is speculation the Cambridges ' second born might arrive on the Queen 's birthday on April 21 or even the Duke and Duchess ' fourth wedding anniversary on April 29 . Other reports suggest the due date could be April 25 . The Duchess of Cambridge is to return to the Lindo wing at St Mary 's Hospital in London to give birth . as she did with Prince George ( pictured ) That date would tally with the fact that the Duchess ' final public engagements before she gives birth were carried out on March 27 in South London , suggesting late April is more likely than mid-April . The Duchess ' second pregnancy was announced on September 8 when she was thought to be just six weeks pregnant . She has been staying at the couple 's new country home in Norfolk , Anmer Hall . But she is expected to return to London soon as she intends to give birth at the Lindo Wing of St Mary 's Hospital , where a natural birth costs up to £10,000 . Her team will be led by Guy Thorpe-Beeston , Surgeon Gynaecologist to the Royal Household . Waley-Cohen is a Celebrity Ambassador for The Bone Cancer Research Trust ( BCRT ) and was famously pictured with the Duchess of Cambridge at the Roller Disco he organised to raise money for a ward in memory of his brother .
The royal baby could be called Sam , after Duchess of Cambridge 's friend . Comment: Odds on the royal baby being named Sam have been slashed from 66/1 to 20/1 since Waley-Cohen appeared at Aintree and won race on Friday . Royal couple have insisted they do not know the sex of their second child .