Friday marked a doubly exciting day for Zara Tindall, as the equestrian got back in the saddle. The eventing season kicked off earlier in March, but Zara's first competition was at Barbury Castle Horse Trials in Wiltshire. The mother-of-three will ride on her own horses, Showtime and Class Affair, during the three-day event. But Zara and her husband, Mike Tindall, also had a personal celebration on Friday 21 March – their son Lucas' birthday. The youngster, who was born in 2021, has previously been seen cheering on his mother during her competitions, alongside his older sisters, Mia and Lena. Lucas was also seen at Cheltenham racecourse with his parents and sisters back in January, with the little boy seen cheering and larking about in the stands. While Mia was born at Gloucestershire Royal Hospital in 2014 and Lena arrived at Stroud Maternity Hospital in 2018, Lucas was actually born at the family's home, located on his grandmother Princess Anne's Gatcombe Park estate. Former rugby star Mike announced his son's birth on The Good, The Bad & The Rugby podcast. "Sunday got even better because a little baby boy arrived at my house," Mike told his co-hosts, Alex Payne and James Haskell. "Arrived very quickly. Didn't make it to hospital. On the bathroom floor. So yeah, it was running to the gym, get a mat, get into the bathroom, get the mat on the floor, towels down, brace, brace, brace." Mike revealed that Zara's friend Dolly Maude, who was also present at the birth of their two daughters, recognised that they wouldn't have time to go to hospital. "Fortunately the midwife who was going to meet us at the hospital wasn't that far away so she drove up just as we had assumed the posit [position] and the second midwife arrived just after the head had arrived," Mike added. Lucas is 25th in line to the throne after his mother and sisters. He was born six weeks after his second cousin, August Brooksbank – the eldest son of Zara's cousin, Princess Eugenie and her husband, Jack Brooksbank. Zara and Eugenie held a joint christening for their sons at Windsor Castle in November 2021. August and Lucas are expected to start school this September. The cousins made a glamorous appearance together at Cheltenham Festival last week, where Zara is a racecourse director. Zara and Eugenie coordinated in burgundy hues as they watched the action at the Gloucestershire racecourse. Queen Camilla, the Princess Royal and a whole host of famous faces were also spotted among the racegoers.